MINE  TRACKS 
THEIR  LOCATION  AND  CONSTRUCTION 


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MINE   TRACKS 

THEIR  LOCATION 
AND  CONSTRUCTION 


TREATING  BRIEFLY  ON  THE  MATERIALS  USED  AND  THE 
PRINCIPLES  INVOLVED  IN  THE  DESIGN  AND  IN- 
STALLATION,  WITH  A  SET  OF  RULES 
FOR  A  STANDARD  PRACTICE 


BY 

J.  McCRYSTLE,  E.  M. 


FIRST  EDITION 
SECOND" 


McGRAW-HILL  BOOK  COMPANY,  INC. 
239  WEST  39TH  STREET.     NEW  YORK 

LONDON:  HILL  PUBLISHING  CO.,  LTD. 
6  &   8  BOUVERIE   ST.,    E.   C. 

1918 


A/3 


*f 


COPYRIGHT,  1918,  BY  THE 
MCGRAW-HILL  BOOK  COMPANY,  INC. 


THE     MAPLE     PRESS     YORK     PA 


INTRODUCTION 

The  gradual  displacement  of  animals  by  mechanical 
haulage  as  the  motive  power  in  mine  transportation,  the 
successive  increases  in  the  weight  of  the  locomotives  em- 
ployed and  the  improvements  in  car  journals  and  rolling 
stock,  admitting  of  longer,  heavier  trains  at  relatively  high 
velocities,  are  making  imperative  a  closer  attention  to  the 
track  material  used  in  mines. 

Short-radius  curves  are  falling  into  disuse  wherever 
traffic  is  at  all  heavy.  These  curves  are  frequently  the 
limiting  factor  in  the  length  of  the  trip.  The  long  wheel- 
base  of  the  motors  is  not  adapted  to  them,  they  are  the 
site  of  continual  derailments,  the  haulage  speed  must  be 
reduced  at  their  approach,  the  cars  cannot  be  pushed 
around  them  without  danger  of  the  bumpers  "locking," 
their  maintenance  is  excessive,  and  for  many  other  reasons 
the  use  of  sharp  curves  is  questionable  economy. 

The  introduction  of  the  steel  car  for  mine  transportation 
also  demands  a  higher  grade  of  trackwork  than  was  re- 
quired for  the  wooden  car;  the  deficiencies  of  the  roadbed, 
to  which  the  semi-pliant  material  of  the  latter  adapted 
itself,  tends  to  loosen  the  construction  of  the  more  rigid 
steel  car. 

With  the  more  progressive  mining  companies,  the  old 
practice  of  building  frogs,  switches,  etc.,  at  the  mine-— to 
suit  the  conditions  as  they  arose — with  the  crude  facilities 
of  the  average  smithshop,  is  being  supplanted  by  the  use 


436311 


vi  INTRODUCTION 

of  better-constructed  commercial  equipment,  to  which  the 
curves  are  standardized.  For  it  is  obvious  that  the  highest 
perfection  in  the  design  and  quality  of  the  material  will 
accomplish  little  if  this  material  is  improperly  installed. 

With  many  mining  companies,  I  have  found,  that  after 
they  are  satisfied  as  to  the  merit  of  the  equipment,  the 
subject  of  trackwork  is  neglected,  and  the  manner  of  in- 
stallation and  the  specific  application,  the  selection  of  the 
frogs,  switches,  etc.,  goes  by  default  to  the  foreman  or 
trackman.  Generally  speaking,  no  efficient  trackwork  can 
be  accomplished  without  some  prescribed  rules  to  govern 
this  work. 

Moreover,  it  will  be  found  in  endeavoring  to  compile  a 
standard  practice  for  the  guidance  of  the  trackmen,  that 
while  most  textbooks  and  handbooks  on  this  subject  are 
replete  with  data  on  the  standard-gage  track,  they  are 
curiously  lacking  when  applied  to  the  narrow  gages.  It  is 
necessary  to  delve  through  many  topics  to  find  any  in- 
formation at  all  on  the  subject,  and  then  often  its  treat- 
ment is  intelligible  to  no  one  but  an  engineer. 

With  the  foregoing  in  mind,  the  following  treatise  has 
been  prepared  in  order  to  furnish  those  in  charge  of  the 
trackwork  and  the  laying  out  of  trackwork  with  the  neces- 
sary data  in  a  convenient  form,  compiled  from  the  usages 
of  several  companies  where  trackwork  has  been  taken  up 
systematically. 

The  introduction  of  the  rules  in  the  latter  part  of  this 
book  is  in  line  with  the  policy  of  the  standard-gage  roads 
to  standardize  practices  and  material,  and  fix  definitely  the 
responsibility  for  the  various  operations.  The  first  part  of 
the  book  deals  briefly  with  the  reasons  governing  the  rules 
and  the  mathematical  computations  involved.  The  opinion 
that  a  mine  car  will  run  on  any  kind  of  track  and  that  any- 


INTRODUCTION  vii 

thing  is  good  enough  for  mine  work  cannot  be  too  strongly 
discouraged. 

Wellington  and  other  authorities  have  been  quoted. 
I  wish  to  thank  Mr.  H.  G.  Houtz  for  the  preparation  of 
the  sketches  and  Mr.  M.  B.  Gerhard  for  much  valuable 
assistance. 

It  is  hoped  that  a  consistent  application  of  the  practices 
suggested  will  result  in  lengthened  trips  and  lower  haulage 
costs;  easier,  more  economic  track  maintenance  with  a 
minimum  of  equipment  in  stock,  and,  finally,  help  to  reduce 
delays  in  transportation  ascribable  to  trackwork. 

J.    McCRYSTLE. 

October,  1917. 


CONTENTS 

PAGE 

INTRODUCTION v 

CHAPTER  I 

RAIL 1 

Stiffness — Strength — Durability — Advantages  of  Heavy  Rail 
— Acid  Water — Method  of  Laying — Defects  in  Laying — Rail 
Benders — Allowance  for  Temperature — Track  Creep — 
Wooden  Rail,  Advantages  and  Disadvantages. 

CHAPTER  II 

TIES 12 

Preferred  Material — Determination  of  the  Spacing — Im- 
properly Supported  Ties — Effect  on  Rail  Stiffness — Coor- 
dination of  Rail  Weight  and  Tie  Frequency — Tables — Calcu- 
lation of  Rail  Deflection — Tamping — Length — Angle  Bars 
and  Fish  Plates — Steel  Ties — Corduroying — Length  for 
Switches — Notched  Ties — Size  of  Spikes — Use  of  the  Plates 
and  Rail  Braces — Effect  on  Rail  Flange — Roadbed  and  Bal- 
last— Material  for  Ballast — Drainage. 

CHAPTER  III 

PROJECTION  OF  HAULAGE  ROADS 31 

Determining  Factors — Curves,  Methods  of  Laying  Out — 
Economic  Radius  of  Curves — Effect  on  Traffic — Alignment 
on  Surface,  Preliminary  Work — Maximum  Degree  of  Curve 
— Curve  Calculations  and  Formula — Calculation  and  Loca- 
tion of  Short  Radius  Curves — Standard  Practice. 

CHAPTER  IV 

GRADES 45 

Definition — Determining  Factors — Traffic,  Drainage — Local 
Features — Underground  Projections — Theoretic  Grades — 
Equalization  of  Drawbar  Pull — Computation — Effect  on 

ix 


x  CONTENTS 

Locomotive  Capacity — Expedients  for  Facilitating  the 
Handling  of  Cars — Effect  on  Mining — Grade  Requirements 
with  Plain  and  Patent  Bearings — Constructing  Grades — 
Grade  Boards — Effect  of  Rail  Curvature. 

CHAPTER  V 

GRAVITY  GRADES.    .    '. 59 

Effect  on  Rolling  Stock — Shafts  and  Slope  Landings — Empty 
and  Loaded  Car  Requirements — Compensation  for  Curva- 
ture— Reversing  of  Compensation — Formulas  and  Computa- 
tions— Rail  Superelevation  on  Curves — Increasing  the  Track 
Gauge  on  Curves,  Underlying  Principles — Wheel  Basis  of 
Cars — Guard  Rail,  Location  and  Method  of  Placing. 

CHAPTER  VI 

FROGS  AND  SWITCHES G8 

Standardization — Frog  Numbers — Plates  Frogs — Cast  Frogs 
— Width  of  Flangeways — Long  Throats — Frogs  for  Different 
Types  of  Work  and  Haulage — Shrouds  for  Frogs — Cast, 
Rigid  and  Spring  Shrouds — Movable  Point  Frogs — Tracks 
Crossings — Split  Switches  and  Latches — Switches  for  Mine 
Work — Switch  Attachments — Formulas — Stub  Switches — 
Tables — Turnouts,  Calculation  of  Lead,  Rail  Length,  Radius, 
etc. — Mine  Practice — Turnout  Tables — Construction  of 
Turnouts — Turnouts  off  Curves. 

CHAPTER  VII 

LOCATING  THE  TURNOUT ' 91 

Method  of  Installing  Frog  and  Switch — Bent  Switch  Points 
— Clearance  at  Heel — Ladder  Tracks — Angle  of  Ladder — 
Distance  between  Frogs. 

CHAPTER  VIII 

BOOK  OF  RULES 93 

Responsibility — Education  of  Trackmen — Conservation  of 
Material — Coordinating  Field  and  Office  Work — Stand- 
ard Practices — General  Rules — Roadbed — Ties — Rail  and 
Spikes — Curves — Angle  Bars,  Tie  Plates  and  Rail  Braces — 
Frogs  and  Switches, 

INDEX.  .   103 


MINE  TRACKS 

THEIR  LOCATION  AND  CONSTRUCTION 

CHAPTER  I 
RAILS 

With  the  exception  of  gravity  roads  on  the  heavier  grades 
where  wood  rail  is  still  preferred  on  account  of  its  higher 
coefficient  of  friction,  standard  tee  rail  is  now  in  general 
use  for  mine  tracks.  In  determining  the  proper  weight  or 
section  of  steel  rail  for  any  work,  the  type  of  haulage,  the 
weight  of  the  cars  and  locomotive,  the  spacing  of  the  ties, 
and  in  some  cases  the  reaction  of  the  acid  or  sulphur  water 
must  be  thoroughly  considered.  The  approximate  rules 
heretofore  used  in  the  determination  of  the  rail  section  have 
usually  erred  in  making  the  rail  section  too  light.  The 
severity  of  future  as  well  as  present  traffic  must  be  consid- 
ered, since  rail  once  laid  is  almost  invariably  utilized  as 
long  as  the  cars  will  travel  over  it,  regardless  of  the  increase 
in  tonnage  both  of  the  trip  and  locomotive. 

In  computing  the  safe  load  for  steel  rail  laid  with  16  ties 
to  the  30-ft.  rail,  10  Ib.  per  yard  for  each  2240  Ib.  of  weight 
on  each  wheel  is  usually  taken;  this,  with  an  8-ton  four- 
wheel  motor,  would  mean  2  tons  on  each  wheel,  or  20-lb. 
rail.  This  weight,  while  safe,  is  evidently  not  enough  for 
any  but  chamber  work — light-weight  rail  is  a  costly 
economy. 

The  flat  wheels  common  to  mine  cars,  the  swaying  side 
motion  due  to  the  play  of  the  axles  in  the  boxes  and  the 
side  slant  of  the  roadbed,  the  inferior  ballast  allowing  some 

1 


'''MINE  TRACKS 

of  the  ties  to  sink  and  causing  the  rail  to  span  a  number  of 
ties,  thus  creating  greater  bending  moments,  the  acid  action 
of  the  water  on  the  steel,  the  scrap  value  of  any  reclaimed 
track,  the  cutting  effect  on  the  treads  of  the  locomotive 
wheels,  etc.,  are  too  often  forgotten  in  the  purchase  of  rail. 

Again,  gangways  or  headings  starting  out  with  short  mule 
hauls  are  converted  to  motor  hauls,  and  later  employed  as 
main  haulageways  without  any  improvement  in  the  original 
track.  As  a  consequence,  the  rail  becomes  a  series  of 
humps  and  hollows,  the  maintenance  of  the  rolling  stock 
and  roadbed  is  excessive,  the  roadbed  is  rendered  dirty  by 
the  car  offal,  the  trips  have  few  cars,  frequent  derailments 
occur,  and  the  initial  economy  in  the  light  weight  of  the 
rail  is  soon  overcome. 

As  Wellington  aptly  expresses  it,  in  buying  rail  "  we  must, 
unfortunately,  use  an  intelligence  somewhat  higher  than  a 
hay  scale."  In  rail  we  require:  (1)  Stiffness,  (2)  strength 
and  (3)  durability,  rather  than  tons  of  steel.  If  the  strength 
of  various  sections  is  compared,  it  will  be  found  that  these 
requisites  can  be  purchased  at  a  lower  unit  rate  in  the  larger 
sections.  In  "stiffness"  we  have  that  property  which  al- 
lows the  rail  to  span  the  ties  and  support  the  load  without 
deflecting,  affording  thereby  a  smooth  running  surface  for 
the  cars;  in  "strength"  we  have  that  quality  which  bears 
the  load  without  breaking,  while  in  "durability"  we  have 
the  ability  to  resist  wear  over  extended  periods  of  time. 

The  stiffness  varies  as  the  square  of  the  weight,  and  the 
strength  as  the  %  power,  while  the  price  per  ton  is  nearly 
constant.  If  the  unit  weight  is  assumed  as  being  30  Ib.  per 
yard,  then  the  stiffness  will  increase  as  follows: 

THIRTY  POUNDS  PER  YARD— STIFFNESS  =  1 

16%  per  cent,  increase  in  weight  (35  Ib.  per  yard)  stiffness  =  1.36  or  a 
36  per  cent,  increase. 


RAILS  3 

33%  per  cent,  increase  in  weight  (40  Ib.  per  yard)  stiffness  =  1.78  or  a 

78  per  cent,  increase. 
50  per  cent,  increase  in  weight  (45  Ib.  per  yard)  stiffness  =  2.25  or  a 

125  per  cent,  increase. 
66%  per  cent,  increase  in  weight  (50  Ib.  per  yard)  stiffness  =  2.79  or  a 

179  per  cent,  increase. 
100  per  cent,  increase  in  weight  (60  Ib.  per  yard)  stiffness  =  4.00  or  a 

300  per  cent,  increase. 

The  ultimate  strength  will  increase  as  follows: 

THIRTY  POUNDS  PER  YARD— ULTIMATE  STRENGTH  =  1 
16%  per  cent,  increase  in  weight  (35  Ib.  per  yard)  ultimate  strength  = 

1.26  or  a  26  per  cent,  increase. 
33%  per  cent,  increase  in  weight  (40  Ib.  per  yard)  ultimate  strength  = 

1.54  or  a  54  per  cent,  increase. 
50  per  cent  increase  in  weight  (45  Ib.  per  yard)  ultimate  strength  = 

1.84  or  a  84  per  cent,  increase. 
66%  per  cent,  increase  in  weight  (50  Ib.  per  yard)  ultimate  strength  = 

2.15  or  a  115  per  cent,  increase. 
100  per  cent,  increase  in  weight  (60  Ib.  per  yard)  ultimate  strength  = 

2.83  or  a  183  per  cent,  increase. 

The  advantages  of  the  heavy  section  over  the  light,  as 
regards  stiffness  and  strength,  would  show  a  higher  com- 
parison as  the  rail  wears  or  wastes  away  from  any  cause 
whatsoever. 

In  determining  the  durability  of  rail,  it  is  obvious  that  a 
great  amount  of  wear  cannot  be  expected  if  the  weight 
selected  conforms  closely  to  the  immediate  duty  it  has  to 
perform. 

We  can  assume  for  practical  purposes  that  half  the  total 
weight  is  in  the  head,  and  that  about  half  of  this  weight,  or 
one-quarter  the  weight  of  the  rail,  can  be  worn  away  before 
the  rail  is  discarded,  if  a  sufficient  margin  of  metal  has  been 
allowed;  otherwise,  the  rail  will  fail  before  it  has  attained 
much  more  than  a  high  polish. 

In  mining  work,  particularly  underground,  with  the 
trackmen  in  absolute  charge,  trackwork,  derailments,  rail 


MINE  TRACKS 


breakage,  etc.,  are  taken  as  part  of  the  day's  routine  and 
pass  unnoticed,  except  that  part  which  appears  indirectly 
in  the  high  maintenance  charges. 

If  we  assume  that  a  wear  of  J^  the  weight  of  the  head  is 
allowed  as  a  safety  factor  in  the  lighter  rail,  then  the  dura- 
bility of  light  and  heavy  sections  will  compare  as  follows : 


1 

"3 
o 

Available"  for  wear 

1 

42  X 

o>  ** 

«*-c£ 

>,  o 

I 

"S 

o>  • 

TJ 

i 

a 

"gS 

C       rt 

o 

•3fi 

a 

c 

- 

0 

s"* 

^ 

1*1 

£  G 

c 

.^H 

3 

—    '- 

c  2 

C    05    Qi 

3d 

43 

5 

43 
• 

J^ 

.§2 

—  S 

ill 

'«*J 

09    **  C 

'3 

'3 

£ 

a-* 

s* 

3  a 

^-^ 

H-0* 

cos^ 

30 

15.0 

7.5 

3.0 

12 

5.5 

1.830 

H 

35 

17.5 

8.75 

3.5 

14 

6.0 

1.710 

Yi 

40 

20.0 

10.00 

4.0 

16 

6.5 

1.625 

% 

45 

22.5 

11.25 

4.5 

18 

7.0 

1.550 

% 

50 

25.0 

12.50 

5.0 

20 

7.5 

1.500 

Ho 

55 

27.5 

13.25 

5.5 

22 

8.0 

1.454 

Hi 

60 

30.0 

15.00 

6.0 

24 

8.5 

1.420 

H2 

Or,  using  30-lb.  rail  as  a  unit,  the  metal  available  for 
wear  would  compare  as  follows: 


Available  for  wear  before  head 

would  become  as  light 

Increase    in 

Weight  in  Ib.  per 

Weight  in 

weight  per 

yard 

head  only 

yard,  per 

Maximum 

Minimum 

cent. 

Ib.  per  cent. 

Ib.  per  cent. 

30 

15 

7.5-100 

3.0-100 

35 

17** 

10.0-133^ 

5.5-183% 

16% 

40 

20 

12.5-166% 

8.0-266% 

33% 

45 

22^ 

15.0-200 

10.5-350 

50 

50     • 

25 

17.5-233H 

13.0-433% 

66% 

55 

27H 

20.0-266% 

15.5-516% 

83% 

60 

30 

22.5-300 

18.0-600 

100 

RAILS 


Briefly,  if  we  were  about  to  build  a  permanent  (so-called) 
narrow-gage  road  for  mine  traffic,  for  which  30-lb.  steel 
would  ordinarily  be  used,  we  would  gain,  by  using  a  60-lb. 
section,  the  economy  in  maintenance,  a  more  easily  oper- 
ated road  with  its  attendant  benefits,  fewer  ties,  fewer 
derailments  and  a  larger  scrap  value  when  the  rail  was 
reclaimed.  Furthermore,  we  would  have  a  stiffness  4 
times,  an  ultimate  strength  2.83  times  and  a  durability 
3  to  6  times  as  great,  for  a  rail  expenditure  but  double 
that  for  30-lb.  steel. 

Some  concerns,  by  purchasing  " second  hand"  rail  from 
the  railroad  companies,  obtain  the  heavier  rail  for  the  same 
price  per  lineal  foot  as  for  new  sections  J^  to  %  their 
weight.  This  quality  of  rail  for  most  mining  purposes  will 
serve  as  well  as  new  sections. 

In  localities  where  acid  water  abounds  the  corroding  of 
the  steel  is  frequently  the  limiting  factor  in  the  life  of  the 
rail.  It  would  be  futile  to  lay  heavy  section  rail  in  locations 
where  the  water  would  soon  destroy  it.  As  the  web  and 
edges  of  the  flange  are  the  portions  destroyed  first,  an  in- 
spection of  the  standard  dimensions  will  evidence  that,  by 
increasing  the  weight,  we  do  not  secure  a  proportionate  in- 
crease in  the  acid-resisting  properties  of  the  rail.  Rail 
weighing  25  Ib.  per  yard  has  been  taken  as  the  basis  or  unit. 


Weight 
of  rail 

Increase 
in  weight, 
per  cent. 

Web 

Ends  of  flange 

Thickness 

Increase  in 
thickness, 
per  cent. 

Thickness 

Increase  in 
thickness, 
per  cent. 

25 

... 

1%4 

.. 

11£4 

.. 

30 

20 

21^4 

11 

11£4 

35 

40 

2%4 

21 

*%4 

9 

40 

60 

2%4 

32 

1%4 

27 

45 

80 

2%4 

42 

1%4 

35 

50 

100 

2%4 

47 

1%4 

36 

60 

140 

3>64 

63 

J%4 

64 

6 


MINE  TRACKS 


In  the  standard  tee  rail,  adopted  by  the  American  Society 
of  Civil  Engineers,  42  per  cent,  of  the  metal  is  in  the  head, 
21  per  cent,  in  the  web  and  37  per  cent,  in  the  flange.  The 
top  corners  are  curved  to  a  jKe-in.  radius,  and  the  car 
wheels  are  designed  to  give  on  this  as  little  friction  as  possi- 
ble; as  the  rail  due  to  the  wear  approaches  more  closely  to 
the  shape  of  the  flange  the  friction  is  augmented.  The 
height  of  the  rail  is  identical  with  the  width  of  the  flange, 
so  if  this  dimension  is  measured  the  weight  can  be 
determined. 

The  table  shows  the  weight  of  rail  per  yard  corresponding 
to  the  height  or  flange  width. 


Weight 

Width  of  flange  or 
height,  in  inches 

Weight 

Width  of  flange  or 
height,  in  inches 

25 

m 

45 

3*^6 

30 

3 

50 

3% 

35 

3^ 

60 

4K 

LAYING  RAIL 

In  laying  rails,  the  joints  should  be  staggered;  that  is,  the 
joints  of  one  rail  should  as  nearly  as  possible  come  opposite 
the  center  of  the  rail  lengths  of  the  opposite  rail.  Lengths 
less  than  10  ft.  should  not  be  used. 

In  Fig.  1  are  shown  a  number  of  defective  joints  exceed- 
ingly common  in  mine-track  construction.  No.  1  shows 
what  is  known  as  a  "dish."  This  is  usually  caused  by  the 
rolling  stock  pounding  down  the  joint.  In  No.  2,  two  objec- 
tions will  be  noticed ;  first,  the  ends  of  the  rail  are  not  butted 
closely  together,  and  second,  the  rails  are  on  different  levels. 
No.  3  shows  two  rails  which  are  not  in  alignment,  probably 
caused  by  not  using  joint  fastenings.  No.  4  is  an  example 


RAILS  7 

of  improper  curvature,  or  lack  of  curvature  in  bending  and 
laying  the  rail.  The  joint  should  be  just  as  symmetrical 
and  easy  running  as  the  remainder  of  the  curve. 

When  the  cars  travel  over  a  joint  such  as  No.  1,  or  a 
"high  joint"  (the  contrary  condition  to  No.  1,  caused  by 
the  rail  creeping  or  being  improperly  laid  or  ballasted),  it 


FIG.  1. — Some  common  faults  in  rail  joints. 

necessarily  forces  one  of  the  wheels  to  rise  above  the  rail; 
the  consequence  is  that  quite  often  the  flange  mounts  the 
rail  and  the  car  is  thrown  off  the  track.  When  the  track- 
man seeks  to  remedy  the  condition,  what  often  seems  the 
natural  thing  to  do  is  to  elevate  the  rail  which  the  car  has 
mounted,  when  really  the  difficulty  is  frequently  on  the 
opposite  rail. 

The  objection  to  a  joint  such  as  illustrated  in  No.  2  (Fig. 
1)  is  apparent.     While  it  may  not  cause  a  derailment,  it 


8  MINE  TRACKS 

sets  the  entire  trip  bumping  and  jogging,  racks  the  rolling 
stock  and  loosens  all  the  "topping"  on  the  cars. 

The  objections  to  a  joint  such  as  is  shown  in  No.  3  are 
not  always  as  striking  as  on  this  figure.  The  track  is 
apparently  not  true  to  gage  at  the  end  of  one  of  the  rails, 
and  the  end  of  the  adjoining  rail  is  probably  loose.  When 
no  joint  fastenings  are  employed,  the  rail  may  spring  later- 
ally during  the  passage  of  a  car  and  immediately  thereafter 
revert  to  its  natural  position.  This  may  derail  the  car, 
which,  if  going  at  some  speed,  will  travel  considerably  be- 
yond the  defective  point  and  tend  to  mislead  thereby  in  its 
detection. 

No.  4  (Fig.  1)  is  the  most  usual  form  of  bad  track.  The 
rail  is  not  curved  uniformly,  and  a  swaying  motion  is  im- 
parted to  the  cars;  if  the  velocity  is  sufficient,  the  flange 
may  run  directly  over  the  rail. 

To  be  sure,  all  derailments  cannot  be  ascribed  to  the 
track,  and  in  some  instances  they  can  be  traced  directly  to 
the  car.  However,  if  the  track  is  in  perfect  condition  the 
car  must  be  unusually  bad  before  it  will  leave  the  track. 

All  rails  should  be  laid  true  to  the  correct  gage  of  the 
track  except  where  allowance  is  made  for  curvature.  The 
practice  of  slightly  reducing  the  gage  of  the  track  to  allow 
for  the  deficiencies  of  the  gage  of  the  car  wheel  is  question- 
able, since  this  expedient  impairs  the  wheel  gage  of  any  new 
cars. 

Fig.  2  shows  an  ordinary  rail  bender,  or  "Jim  Crow," 
adapted  for  bending  heavy  rails  or  "dishing"  them.  The 
contrivance  consists  of  two  eye-bolts,  two  old  sticks  of  tim- 
ber, two  mine  ties  and  a  rail  bender.  The  greater  the  spac- 
ing of  the  ties,  the  greater  will  be  the  power  of  the  bender. 

Rail  which  has  previously  been  used  for  locomotive  haul- 
age will  frequently  be  found  to  be  brittle  and  break  during 


RAILS 


9 


bending.  This  condition  is  due  to  the  crystallization  of 
the  steel  from  the  constant  impact  of  the  wheels  and  docs 
not,  as  is  often  erroneously  believed,  arise  from  the  return 
passage  of  electric  currents.  The  effect,  if  any,  of  the  elec- 
tricity would  be  to  soften  the  metal.  However,  where  the 
bonding  of  the  rails  is  deficient,  the  electric  current  some- 
times leaves  the  rail  and  runs  through  the  soil,  again  return- 


FIG.  2. — Rail  bender,  adapted  for  "dishing"  rails. 

ing  to  the  rail.  This  leaving  and  reentering  the  rail  causes 
an  electrolytic  action,  and  the  rail  sometimes  disintegrates 
at  the  points  of  exit  and  entry. 

Where  the  rails  have  crystallized,  or  become  brittle,  they 
should  be  either  annealed  before  bending  or  be  bent  while 
hot. 

Where  rails  are  laid  underground,  the  small  variation  in 
the  temperature  will  not  require  any  allowance  at  the  joints 
for  expansion;  when  they  are  laid  on  the  surface,  however, 


10  MINE  TRACKS 

the  space  left  for  the  expansion  of  30-ft.  rails  should  be  as 
follows: 

Temperature  when  Space  to  be  allowed 

rail  is  laid  for  expansion 

24  deg.  and  less  %  in. 

25  deg.  to  49  deg.  %6  in. 
50  deg.  to  74  deg.  %  in. 
75  deg.  to  94  deg.  y[G  in. 
95  deg.  and  over  Nothing 

On  tracks  on  a  heavy  grade  the  rails  have  a  tendency  to 
" creep"  or  move  down  the  grade.  This  may  be  caused 
either  by  the  braking  of  the  train,  or  the  tractive  force  of 
the  locomotive,  or  a  combination  of  both;  the  effect  of  the 
braking  being  the  more  appreciable  due  to  the  unevenness 
of  its  application,  and  will  be  more  evident  in  the  down 
track  or  roads  having  one  way  traffic. 

The  " creep"  is  caused  by  a  longitudinal  thrust,  com- 
municated by  the  wheels  to  the  rail,  and  is  equivalent  to 
20  per  cent,  of  the  weight  of  the  locomotive  where  the  cars 
are  not  equipped  with  brakes,  and  20  per  cent,  of  the  com- 
bined weight  of  the  cars  and  locomotives  on  a  down  grade 
where  the  brakes  on  the  cars  and  locomotive  are  applied. 

This  "creep"  destroys  the  alignment  of  the  track  and 
curves,  and  at  sites  where  it  is  found  impossible  to  re-align 
the  track  without  cutting  the  rail,  the  excess  length  should 
be  bent  outward  and  permitted  to  slide  without  distorting 
the  track.  This  is  accomplished  by  inserting  a  switch  point 
at  the  bent  rail  to  make  a  sliding  contact  instead  of  the 
usual  unyielding  butt  connection.  Their  use  at  the  upper 
end  of  the  curves  will  be  found  advantageous. 

WOODEN  RAIL 

In  flat  pitch  mining,  where  the  car  is  taken  by  gravity 
from  the  working  face,  with  the  wheels  spragged  to  retard 


RAILS  11 

the  velocity,  wood  rail  is  frequently  used  on  account  of  its 
higher  coefficient  of  friction,  or  resistance  to  sliding.  This 
coefficient  for  cast  iron  on  steel  is  0.20,  and  for  cast  iron 
on  oak  0.49,  or  about  2J£  times  as  great  for  the  wooden  rail. 

It  is  problematical  whether  the  use  of  wood  rail  is  war- 
ranted under  any  conditions.  Many  mines  have  discon- 
tinued its  use  without  any  noticeable  inconvenience  on  their 
heavier  pitching  " slants,"  or  chambers.  The  required  fric- 
tion is  obtained  by  running  a  plank  along  the  outside  of  a 
light  tee  rail.  The  tread  of  the  wheel  being  wider  than  the 
head  of  the  rail  allows  the  wheels  to  slide  upon  both  the 
plank  and  the  tee  rail. 

Among  the  objections  to  wood  rail  are:  The  lack  of 
durability;  the  rounding  of  the  corners  and  the  splintering 
of  the  wearing  surface,  due  to  the  action  of  the  wheels; 
the  lack  of  uniformity  of  the  cross-section  and  the  inclina- 
tion to  warp,  common  to  all  wood.  Owing  to  these  draw- 
backs and  the  ease  with  which  the  car  wheels  mount  wooden 
rail,  the  cars  are  much  more  subject  to  derailments  than 
when  steel  rail  is  employed. 

Wood  rails  are  usually  laid  in  ties  which  have  been 
notched  to  the  proper  gage  and  are  held  in  place  by  the 
notches  and  steel  spikes.  They  can  be  laid  almost  as 
rapidly  as  the  light  weight  steel  rail. 

The  rail  is  usually  ordered  about  3X5  in.  in  section 
and  in  12  to  16-ft.  lengths  of  beech,  birch,  maple,  oak 
or  ash.  Care  should  be  taken  to  have  such  rails  sound 
with  square  edges,  and  to  have  them  stored  in  a  man- 
ner to  prevent  warping. 


CHAPTER  II 
TIES 

The  dimensions  of  mine  ties  should  be  consistent  with 
the  rail  and  spikes  used,  and  the  mode  of  haulage.  In 
order  to  insure  stability,  the  ties  should  in  no  case  extend 
less  than  8  in.  beyond  the  web  of  the  rail;  nor  should  they 
be  less  than  4J^  ft.  in  length.  In  addition,  the  ties  should 
have  two  parallel  faces  at  least  3%  in.  wide.  The  pre- 
ferred woods  are  locust,  oak,  chestnut,  hemlock,  ash,  iron- 
wood,  hickory  and  hard  pine. 

With  usual  conditions,  the  number  of  cross-ties  cannot 
be  too  great  for  service  until  their  closeness  to  each  other 
impedes  tamping,  which  limit  is  reached  when  about  40 
per  cent,  of  the  rail  rests  upon  the  ties.  The  determination 
of  the  tie  spacing  is  dependent  on  (1)  the  weight  of  the  rail, 
(2)  the  packing  and  ballast  of  the  ties,  and  (3)  the  weight 
and  volume  of  the  traffic 

With  a  tie  having  a  6-in.  face  the  minimum  spacing 
to  allow  adequate  tamping  would,  therefore,  be  15  in. 
This,  however,  is  a  tie  frequency  that  practically  it  is  almost 
impossible  to  obtain  under  the  more  usual  mining  conditions 
in  which  the  workmen  driving  the  headings  or  chambers, 
are  also  required  to  extend  their  own  track.  With  these 
men,  the  track  work  being  but  a  secondary  consideration, 
the  natural  tendency  is  to  give  it  only  enough  attention  to 
fulfill  their  immediate  needs  and  satisfy  the  none  too 
strict  exactions  of  the  mine  foremen. 

In  ascertaining  the  proper  tie  spacing  or  the  weight  of 
rail  suitable,  the  following  consideration  must  not  be  lost 

sight  of. 

12 


TIES  13 

(1)  Allowance  should  be  made  for  unusual  impact  stresses 
caused  by  the  "flat  spots"  on  car  wheels.     These  "flat 
spots"  are  quite  common  on  wheels  in  mines  having  long 
grades  requiring  sprags.     The  load  transferred  to  a  rail 
by  a  flat  wheel  on  a  car  in  motion  is  in  the  nature  of  a  blow 
or  suddenly  applied  load,  and  will  therefore  be  more  severe 
than  a  smoothly  applied  moving  load. 

(2)  Consideration  should  be  given  to  the  frequent  occur- 
rence of  ties  that  are  not  adequately  supported  by  the 
ballast,  which  may  be  due  not  only  to  improper  tamping, 
but  also  to  the  washing  out,  or  disintegration  of  the  ballast. 
This  occurrence  will  at  least  double  the  stipulated  span  of 
the  rail. 

(3)  Due  thought  should  be  given  to  the  great  loss  in 
rail  stiffness  caused  by  but  a  small  increase  in  space  between 
the  ties.     A  failure  to  observe  this  will  soon  be  evident  in 
"dishes"  in  the  rail,  and  the  effects  on  the  traffic.     It  will 
be  recognized   readily  that  if  the  ties  are   welL  packed, 
any  increase  in  the  number  of  ties  used  for  a  given  distance 
will  increase  the  strength  and  stiffness  of  the  rail.     Accord- 
ingly, if  the  rail  furnished  is  too  light  for  the  traffic,  this 
deficiency  may  to  a  large  extent  be  overcome  by  the  use  of 
more  ties.     Ties  must  be  well  tamped  before  they  can  be 
expected  to  perform  their  proper  function  of  supporting 
the  rail  and  load. 

A  few  concrete  examples  will  perhaps  make  clear  the 
foregoing  considerations  in  the  computation  of  the  weight 
of  rail  and  tie  spacing  with  various  rolling  stocks. 

Example. — It  is  desired  to  establish  a  safe  weight  of 
rail  for  use  with  a  4-wheel,  8-ton  locomotive,  having  a  4-ft. 
wheel  base,  drawing  cars  with  a  maximum  gross  weight 
of  7  tons,  and  having  a  2>^-ft.  wheel  base  over  ties  having 
6-in.  faces  and  spaced  on  24-in.  centers. 


14  MINE  TRACKS 

Weight  on  one  locomotive  wheel  =  —  ~—  =  4000  Ib. 

Weight  on  one  car  wheel  =  —  4  —  =  3500  Ib. 

Since  the  rail  is  continuous  over  the  ties,  the  rail  between 
adjacent  ties  can  be  regarded  as  a  beam  with  fixed  ends. 
The  effect  of  a  suddenly  applied  load  is  twice  that  of  a 
stationary  load. 

The  usual  allowable  stress  per  square  inch  in  steel  shapes 
used  as  beams  is  16,000  Ib.,  compression  or  tension,  when 
stationary  loads  are  considered.  Hence,  the  allowable 
stress  in  this  example  will  be  8000  Ib.  per  square  inch. 

Now  the  maximum  bending  moment  produced  on  a  beam 
by  a  single  concentrated  load  =  -^Pl  where  P  =  load  in 
pounds  and  I  =  space  between  supports  in  inches.  But  the 

bending  moment  (M)  in  any  beam  also  equals  S-,  where 

S  equals  allowable  stress  per  square  inch  and  -  =  section 

c 

modulus  of  the  beam. 
Hence, 


Or  8000  X  -  •-  JfX  4000  X  18 

C 

which  reduces  to 

I      1  X  4000  X  18       g/ 
c=        8  X  8000  %  = 

By  consulting  tables  of  "T"  rail  sections  in  Cambria 
Steel  Company's  Handbook,  it  is  seen  that: 
The  section  modulus  of  16  Ib.  rail  =     .75 
The  section  modulus  of  20-lb.  rail  =  1.30. 
From  the  above  it  is  evident  that  a  16-lb.  rail  is  too  light, 


TIES  15 

and  therefore  the  20-lb.  rail,  although  the  section  modulus 
is  somewhat  higher  than  required,  is  used. 

In  the  above  illustration,  it  will  be  noted  that  the  weight 
on  one  locomotive  wheel,  which  is  greater  than  that  due  to 
one  car  wheel,  is  used,  and  further  that  each  tie  is  accepted 
as  doing  its  full  duty. 

In  the  event,  however,  of  a  tie  failing  to  contribute  its 
proper  support,  which  is  very  often  the  case,  the  span  of 
the  rail  would  be  increased  from  18  to  42  in.  On  this  in- 
creased span  there  ordinarily  will  be  space  for  two  car 
wheels,  but  only  one  locomotive  wheel,  in  which  case: 

Maximum  bending  moment  due  to  locomotive  =  %Pl  as 
before. 

In  any  condition  where  the  wheel  base  is  more  than  0.586 
of  the  span,  the  bending  moment  due  to  two  loads,  as  with 
the  two  wheels  on  the  mine  car,  would  not  be  as  great  as 
the  bending  moment  due  to  the  weight  on  a  single  wheel  in 
the  center  of  the  span.  This  relation  is  true  regardless  of 
the  position  of  the  two  wheels. 

In  the  case  cited  then,  in  which  one  tie  is  not  contributing 
support  and  the  span  instead  of  18  in.  is  now  42  in., 
the  greatest  weight  on  one  wheel,  whether  from  the  loco- 
motive or  car  wheel,  would  be  used  in  the  preceding  formula, 

S—  =  y%Pl.     Substituting    the    known   quantities  in   the 

formula  and  using  the  weight  on  one  locomotive  wheel  as 
an  illustration,  with  the  42-in.  span,  the  following  value 

of  2.625  is  obtained  for  —     This,  by  referring  to  tables  of 

C 

"T"  rail  sections,  is  found  to  indicate  35-lb.  rail. 

The  preceding  formulae  show  that  the  bending  moment 

"M,"    and    consequently   the   section   modulus   ->    vary 

C 

directly  as  the  span  and  the  load. 


16 


MINE  TRACKS 


The  following  tables,  based  on  allowable  stress  of  8000 
Ib.  per  square  inch,  show  the  section  modulus,  with  the 
corresponding  weight  of  rail,  and  the  allowable  weight 
per  wheel  for  the  usual  tie  spacings  encountered.  The 
designated  weights  per  wheel,  starting  at  1000  Ib.,  and 
varying  by  successive  increments  of  1000  Ib.  up  to  10,000 
Ib.,  will  cover  any  wheel  loads  liable  to  be  encountered  in 
mine  practice. 

TABLES  OF  RAIL  SECTIONS  AND  TIE  SPACING 
(Ties  with  6-in.  faces) 


Weight  on  one 
wheel 

Specified  tie  centers  —  24  in. 

Resulting  span  (42  in.)  on  alter- 
nate ties 

Section 
modulus 

Weight  of  rail, 
pounds  per 
yard 

Section 
modulus 

Weight  of  rail, 
pounds  per 
yard 

1,000 

0.281 

8 

0.656 

16 

2,000 

0.562 

12 

1.312 

20 

3?000 

0.843 

16 

1.969 

30 

4,000 

1.125 

20 

2.625 

35 

5,000 

1.406 

25 

3.281 

40 

6,000 

1.688 

25 

3.937 

45 

7,000 

1.969 

30 

4.594 

50 

8,000 

2.250 

30 

5.250 

55 

9,000 

2.531 

35 

5.906 

55 

10,000 

2.813 

35 

6.562 

60 

Specified  tie  centers—  21  in. 

Resulting  span  (36  in.)  on  alter- 
nate ties 

1,000 

0.234 

8 

0.562 

12 

2,000 

0.468 

12 

1.124 

20 

3,000 

0.702 

16 

1.686 

25 

4,000 

0.936 

16 

2.250 

30 

5,000 

1.170 

20 

2.812 

35 

6,000 

1.404 

25 

3.376 

40 

7,000 

1  .  638 

25 

3.938 

45 

8,000 

1.872- 

30 

4  .  500 

50 

0,000 

2.106 

30 

5.062 

55 

10,000 

2.340 

35 

5.626 

55 

TIES 


17 


TABLES  OF  RAIL  SECTIONS  AND  TIE  SPACING. — (Continued) 
(Ties  with  6-in.  faces.) 


Specified  tie  centers  —  18-in. 

Resulting  span  (42  in.)  on  alter- 
nate ties 

Weight  on  one 

wheel 

Section 

Weight  of  rail, 

Section 

Weight  of  rail, 

modulus 

pounds  pei- 

modulus 

pounds  per 

yard 

yard 

1,000 

0.187 

8 

0.463 

12 

2,000 

0.374 

12 

0.936 

16 

3,000 

0.561 

12 

1.404 

25 

4,000 

0.748 

16 

1.872 

30 

5,000 

0.936 

16 

2.340 

35 

6,000 

1.123 

20 

2.808 

35 

7,000 

1.310 

20 

3.276 

40 

8,000 

1.497 

25 

3.744 

45 

9,000 

1.684 

25 

4.212 

45 

10,000 

1.871 

30 

4.630 

50 

Specified  tie  centers  — 

Resulting  span  (24  in.)  on 

15  in. 

alternate  ties 

1,000 

0.141 

8 

0.374 

12 

2,000 

0.281 

8 

0.748 

16 

3,000 

0.422 

12 

1.122 

20 

4,000 

0.563 

12 

1.496 

25 

5,000 

0.703 

16 

1.872 

30 

6,000 

0.844 

16 

2.246 

30 

7,000 

0.985 

20 

2.620 

35 

8,000 

1.125 

20 

2.994 

40 

9,000 

1.266 

20 

3.368 

40 

10,000 

1.407 

25 

3.742 

45 

NOTE: — Rail  sections   are  American  Society  of   Civil  Engineers' 
standards. 


From  the  preceding  table,  the  weight  of  rail  required  for 
a  given  tie  spacing  arid  weight  per  wheel,  can  be  taken 
direct,  or  if  a  certain  weight  of  rail  has  been  determined 


18  MINE  TRACKS 

upon,  the  tie  spacing  can  be  fixed  to  give  the  required 
support. 

It  will  be  evident  to  anyone  familiar  with  the  ballast, 
tamping,  and  drainage  around  mines,  that  a  different 
standard  of  tie  spacing  and  rail  will  be  required  for  under- 
ground as  distinct  from  surface  track.  Track  on  the 
surface  will  usually  be  found  much  superior  to  track  of 
similar  equipment  underground. 

This  is  due  to  a  variety  of  causes,  such  as  inferior  align- 
ment, poorer  ballast,  smaller  ties  not  spaced  uniformly, 
and  more  exacting  drainage  conditions.  Track  frequently 
considered  satisfactory  in  the  mines  would  not  be  tolerated 
on  the  surface. 

Where  the  ballast  and  tamping  are  in  good  shape  and 
readily  open  to  inspection,  as  on  the  surface,  the  rail  sections 
shown  for  the  specified  centers  will,  I  believe,  be  found 
satisfactory.  For  the  usual  condition  underground,  the 
heavier  sections  shown  are  recommended  as  none  too  heavy. 

It  is  not  practical  to  vary  the  rail  weight  to  satisfy  every 
condition.  The  large  companies  usually  adopt  a  standard 
for  their  entire  system,  as  it  would  entail  too  much  incon- 
venience and  confusion  to  order  rail  suitable  to  specific 
conditions.  The  tie  spacing,  however,  is  not  subject  to 
arbitrary  restrictions,  and  can  usually  be  adapted  by  the 
local  colliery  officials  to  suit  the  considerations  peculiar 
to  any  section. 

The  greatest  attention  should  be  given  to  selecting  the 
proper  weight  rail  or  tie  spacing  to  conform  with  the  other 
material  used,  their  installation,  and  the  severity  of  the 
traffic. 

In  favor  of  using  heavy  rail,  the  greater  durability, 
stiffness  and  strength,,  the  fewer  ties  required  with  the 
consequently  smaller  expense  of  renewals,  the  higher 


TIES  19 

scrap  value,  the  easy  maintenance  of  the  alignment,  the 
saving  in  the  upkeep  on  the  rolling  stock  due  to  the  better 
riding  qualities,  and  the  potential  ability  to  meet  unforeseen 
increases  in  the  traffic,  must  not  be  forgotten. 

You  will  note  that  the  rail  section  calculated  for  24  in.- 
tie  centers  corresponds  to  the  weight  as  determined  by  the 
empirical  rule  given  for  well  ballasted  track  in  Chapter 
I,  on  "Rail." 

It  might  be  interesting  to  note  in  connection  with  the 
tables  of  rail  and  tie  spacings,  what  degree  of  stiffness, 
as  indicated  by  the  deflection,  will  be  obtained. 

The  maximum  allowable  deflection  or  sag  under  load 
will  evidently  be  realized  when  the  stresses  caused  by  the 
wheel  load  reach  the  elastic  limit  of  the  steel,  which  for 
medium  steel,  referring  to  "Merriman's  Civil  Engineer's 
Pocket  Book,"  is  36,000  Ib.  Accepting  this  value  and 
assuming  the  case  of  the  8-lb.  rail  recommended  for  24- 
in.  tie  centers  (18-in.  clear  span)  with  a  1000-lrir  wheel 
load,  to  find  the  maximum  allowable  and  actual  deflec- 
tion, and  the  allowable  load  within  this  elastic  limit,  we 
have  the  following  formulae: 

(1)  M   (Bending  Moment)  =  S  (36,000  Ib.)  X  *  (Sec- 
tion Modulus). 

(2)  M   (Bending  Moment)  =  J£P  (Superimposed  load) 
X  I  (the  span). 

In  formula  (1)  the  section  modulus  of  8-lb.  rail  is 
ascertained,  by  referring  to  tables  of  "T"  rail  sections,  to 
be  0.31.  Substituting,  M  =  36,000  X  0.31  =  10,850  in.-lb. 

The  allowable  value  of  "P"  with  the  given  span,  and 
the  8-lb.  rail,  is  determined  by  substituting  in  formula 

ol\f 

(2);    where    M  =  %Pl',    transposing,   P  =  — ;  substitu- 


20  MINE  TRACKS 

10  850 
ting  the  known  values,  P  =  8  X  -      -  or  4820  lb.,  which 

o 

as  the  stipulated  moving  load  is  but  1000  lb.  or  equivalent 
•to  2000  Ibs.  static,  gives  a  safety  factor  of  almost  2% 
based  on  the  elastic,  limit. 

The  maximum  allowable  deflection  or  sag  is  expressed  by 

Pit 
the  formula  D  =   inoi  m  which  P  and  I  are  the  same 


as  in  the  preceding  formulae;  E  is  modulus  of  elasticity 

29,000,000;  and  I,  the  moment  of  inertia,  obtained  from  the 

table  of  "T"  rail   sections,   being  0.23  for  an  8-lb.  rail. 

Substituting  these  values  to  find  the  maximum  allowable 

,   .  4820  X  fl8)3 

deflection,   and   solving:    D  =  ^  x  ^^-^-^  = 

0.02188  in. 

Calculating  the  deflection  for  a  wheel  load  of  1000  lb.  (mov- 

2000  X  (18)3 
ing  load  2000  lb.  static  load)  ;  D  --  . 


=  0.0091  inches,  which  shows  that  the  rail  specified  is  well 
within  the  limit  of  maximum  stress. 

If  it  can  be  accepted  that  each  tie  will  contribute  its 
full  quota  of  support  to  the  rail,  the  8-lb.  section  will 
be  suitable  for  the  stipulated  tie  centers  of  24  in.,  but, 
however,  actual  experience  has  proved  that  this  is  not  to  be 
depended  upon,  so  that  some  allowance  must  be  made  for 
imperfections  in  the  tie  support. 

In  the  tables  previously  advanced,  the  rail  for  the  given 
tie  centers,  and  the  rail  required  for  alternate  tie  centers 
has  been  given.  The  use  of  the  rail  for  the  alternate  centers 
is  considered,  in  the  light  of  actual  experience,  none  too 
heavy  for  the  specified  centers,  allowing  as  it  does  for  the 
failure  of  every  other-  tie.  Many  mining  companies  con- 
sider it  economical  in  the  end  to  go  even  further  than  this. 


TIES  21 

It  is  difficult  to  say  just  where  to  draw  the  line,  but  the 
assumed  condition  of  alternate  ties  failing,  makes  a  fair 
allowance  for  ordinary  roadbed  without  going  to  extremes. 

With  the  8-lb.  rail  on  the  42-in.  span,  the  maximum 
allowable  bending  moment  is  found  by  the  preceding  for- 
mula to  be  2065  in.-lb.,  and  the  allowable  deflection 
0.1195  in. 

As  the  moving  load  of  1000  Ib.  is  equivalent  to  a 
static  load  of  2000  Ib.,  it  will  be  seen  that  practically  no 


FIG.  3. — Light  tic  poorly  tamped. 

factor  of  safety  is  allowed,  and  the  8-lb.  rail  is  to~o  light 
for  the  increased  span.  The  resulting  deflection  will 
approach  very  closely  the  maximum  allowable  deflection 
of  O.li95in. 

As  stated  before,  no  fixed  rules  can  be  given  for  determ- 
ining absolutely  the  proper  rail  section  to  be  adopted. 
The  preceding  formulae  and  illustrations  are  given  in  order 
that  the  tie  spacing  and  rail  can  be  coordinated  for  any 
given  conditions  at  hand  or  anticipated.  Even  the  tables 
presented  are  but  a  guide  to  the  selection  of  the  most  suita- 
ble rail  and  tie  spacing. 

Each  tie  should  be  tamped  uniformly  and  particular 
attention  given  to  tamping  under  that  portion  upon 
which  the  rail  rests.  Fig.  3  illustrates  a  case  of  light 
ties  and  improper  tamping.  Fig.  4  shows  the  effect 
on  the  rail  of  poor  tamping  or  ballast. 


22 


MINE  TRACKS 


Again,  referring  to  Fig.  3,  it  may  be  stated  that  with 
improper  ballast  or  tamping  a  tie  of  excessive  length  will  be 
distorted  more  readily  than  one  of  proper  length.  While 
the  long  tie  justly  meets  with  much  favor  on  account  of  its 
greater  bearing  qualities,  there  is  a  limit  to  which  this 
length  can  be  advantageously  utilized.  The  tie  may  be 
considered  as  inverted,  with  the  rails  for  the  supports, 
and  the  pressure  on  the  roadbed  due  to  the  weight  of  traffic 
acting  as  a  uniformly  distributed  load  on  the  tie. 


FIG.  4. — Effect  of  poor  tamping  on  rail. 

The  portions  of  the  tie  outside  of  the  rails  are  then  canti- 
lever beams,  and  the  portion  between  the  rails,  a  beam  with 
fixed  ends. 

In  order  to  obtain  a  tie  length  in  which  the  overhanging 
ends  will  be  of  the  same  strength  as  the  center  portion,  it 
will  be  found  mathematically  that  the  length  of  the  tie 
should  be  1.8  times  the  distance  between  the  rail  centers. 
Of  course,  if  the  tie  is  heavier  than  required,  this  length 
can  be  exceeded  within  limits.  There  are  so  many  indeter- 
minate factors  entering  into  the  computation  of  the  tie 
thickness  that  it  is  futile  to  attempt  to  formulate  any 
definite  rules.  Experience  is  the  only  reliable  guide  in 
this  matter.  However,  it  may  be  said  that  if  the  rail  com- 


TIES  23 

ports  with  the  traffic  and  the  spike  in  turn  is  adapted  to 
the  rail,  then  a  tie  with  a  cross-section  great  enough  to  carry 
the  spike  without  splitting  and  allowing  it  to  protrude 
below,  will  be  of  sufficient  strength  if  its  length  is  not  greatly 
in  excess  of  1.8  times  the  gage. 

When  placing  ties  at  rail  joints  where  angle  bars  are 
employed,  selected  ties  of  uniform  size  should  be  used. 
These  should  be  so  spaced  as  to  give  the  angle  bar  suffi- 


FIG.  5. — A.   Proper    angle    bar    support — incorrect    fish  plate  support. 
B.  Proper  fish  plate  support.     Incorrect  angle  bar  support: 

cient  bearing  and  permit  efficient  spiking — the  rail  joint 
itself  to  be  suspended  midway  between  the  ties.  The 
joint  should  not  be  directly  supported. 

Where  strap  plates  or  fishplates  are  used,  a  selected 
tie  should  be  placed  directly  under  the  joint.  This  also 
applies  where  the  rails  are  butted  together  and  not  bolted. 
The  ties  should  be  spaced  as  close  as  practicable  at  the  rail 
joint. 

The  closer  tie  spacing  would  seem  to  be  peculiarly  adapted 
to  headings  where  the  acid  water  quickly  destroys  the  rail, 
the  use  of  the  lighter  sections  with  a  greater  tie  frequency 
recommending  itself  on  account  of  the  low  initial  cost  and 
the  ability  to  withstand  the  acid  proportionally  better 


24  MINE  TRACKS 

than  the  more  heavy  rail.  There  is,  of  course,  also  the 
lesser  loss  in  the  event  that  the  rail  cannot  be  reclaimed  or  is 
destroyed  prematurely. 

The  use  of  the  steel  tie  for  mine  work  is  generally  con- 
fined to  low  veins  where  height  is  at  a  premium.  As  the 
usual  method  is  to  lay  such  ties  on  the  floor  of  the  haulage- 
way  or  chamber  without  any  ballast,  the  acidity  of  the 
water  must  be  given  due  consideration.  If  properly  placed 
and  taken  care  of,  they  will  outlast  wood  ties,  especially 
in  chambers  where  the  frequent  removal  and  relaying  of 
track  is  the  limiting  factor  in  the  life  of  the  tie.  Some  mines 
use  the  steel  tie  interspersed  at  intervals  with  wood  ties,  in 
the  capacity  of  a  tie-rod  to  hold  the  rails  to  gage. 

The  practice  known  as  "  corduroying " — that  is,  placing 
additional  ties,  or  laggings,  between  other  ties — should 
not  be  employed  where  it  is  necessary  to  reinforce  decayed 
ties  or  to  help  bear  the  stresses  of  heavier  traffic,  except 
possibly  where  mule  haulage  is  the  means  of  transportation. 
This  practice  prevents  efficient  tamping  and  impairs  the 
drainage  of  the  roadbed. 

At  switches,  many  companies  are  in  favor  of  having 
the  ties  in  graded  lengths,  so  as  to  furnish  support 
and  hold  in  alignment  both  tracks  up  to  and  including 
the  frog. 

The  ties  used  in  conjunction  with  wood  rail  are  usually 
made  with  notches.  These  are  cut  to  the  gage  of  the  track, 
so  as  to  hold  the  rails  and  prevent  them  from  tipping  or 
spreading.  While  it  is  not  always  done,  it  is  better  to  have 
the  bottom  side  of  the  tie  faced  to  prevent  the  tie  from  turn- 
ing and  the  track  from  creeping. 

It  is  the  general  opinion  that  ties  will  last  longer  if  the 
bark  is  removed,  and  that  the  hewed  tie  is  more  serviceable 
than  the  sawed  tie. 


TIES 
HOOK  SPIKES 


25 


The  dimensions  of  the  proper  hook  spike  to  be  employed 
should  be  in  accord  with  the  weight  of  the  rail  and  the 
cross-section  of  the  tie.  The  weight  of  the  rolling  stock 
does  not  require,  nor  will  the  general  run  of  mine  ties 
permit  the  use  of  as  large  a  spike  as  is  employed  on  standard- 
gage  track. 

Where  the  ties  will  stand  it,  the  following  sizes  of  spikes 
are  recommended: 


Weight  of  rail  per  yard 

Size  of  spike  in  inches 
measured  under  head 

Average  number  per  keg 
of  200  Ih. 

45  to  70 

5l/2  by  %6 

375 

40  to  60 

5      by%6 

400 

35  to  40 

5      by^ 

450 

30  to  35 

4Mby^ 

530 

25  to  35 

4      by^ 

600 

20  to  30 

4K  by  KG 

680 

16  to  25 

4      by% 

1,000 

16  to  25 

3K  by  KG 

900 

With  such  ties  as  are  ordinarily  used,  however,  the 
X  M-in-  spike  will  probably  be  the  largest  permissible 
size.  In  driving  the  spike,  the  last  blows  should  be  light, 
to  avoid  breaking  the  spike  under  the  head  and  to  make 
a  tighter  bind;  also,  the  two  inside  spikes  should  be  near 
one  side  of  the  tie  and  the  two  outside  spikes  near  the 
opposite  side,  to  prevent  tie  splitting.  If,  when  a  spike 
is  withdrawn,  a  wooden  plug  is  driven  into  the  spike  hole, 
the  life  of  the  tie  will  be  prolonged  considerably. 

Unless  the  spikes  are  known  to  be  in  good  condition, 
it  is  doubtful  whether  it  pays  to  remove  them  when  track 
is  reclaimed;  it  is  comparatively  costly  to  straighten 


26  MINE  TRACKS 

them,  and  if  they  are  not  in  good  shape  the  trackman  will 
probably  throw  away  the  poorer  ones.  Moreover,  old 
spikes  are  difficult  to  drive. 

Many  trackmen,  when  the  ties  are  to  be  reused,  allow 
the  outer  spikes  to  remain  and  deliver  the  ties  with  these 
spikes  in  them  to  the  new  location;  or  when  the  ties  are 
of  no  further  value,  they  are  burned  and  the  spikes  then 
collected. 

There  is  no  doubt  that  with  the  majority  of  mining 
companies  there  is  a  vast  waste  in  the  consumption  of 
spikes,  and  if  a  check  is  kept  on  the  amount  of  track 
laid  this  can  be  readily  verified.  Usually  it  will  be  found 
more  economical  to  distribute  the  spikes  in  a  systematic 
manner  than  to  spend  too  much  time  on  their  reclamation. 
A  good  practice  is  to  have  someone  who  is  conversant  with 
the  needs  of  the  different  workmen  oversee  the  distribution 
of  the  spikes. 

ANGLE  BARS  AND  FISHPLATES 

When  a  locomotive  or  a  trip  of  cars  runs  on  rails,  a 
wave  of  elasticity  precedes  it.  The  object  of  the  joint 
fastening  should  be  to  make  this  wave  continuous  across 
the  joint.  The  ideal  rail  joint  should  have  the  same 
strength,  stiffness  and  elasticity,  both  vertically  and 
laterally,  as  the  rails  which  it  joins. 

That  the  angle  bar  is  much  superior  to  the  fishplate 
in  achieving  this  object  will  be  apparent  from  a  study 
of  the  two.  The  strap  plate  and  the  simplest  forms  of 
angle  bar  are  the  only  types  employed  for  mine  tracks. 

In  Fig.  5-A  is  shown  an  angle  bar  properly  placed  with 
the  rail  gap  suspended  between  the  ties.  By  this  arrange- 
ment the  stress  at  the  joint,  where  there  is  always  more 
or  less  pounding  from  the  traffic,  is  distributed  upon  two 


TIES  27 

ties  instead  of  one  through  the  bridging  action  obtained 
from  the  shape  of  the  angle  bar.  The  stress  at  the  joint 
is  transmitted  to  this  angle  bar  in  such  manner  as  to  produce 
tension  in  the  lower,  or  angle,  portion  of  the  bar. 

If  a  tie  is  placed  directly  under  the  joint,  as  in  Fig. 
5-B,  and  it  becomes  depressed  or  battered,  which  it  will 
in  a  short  time,  the  rail  is  compelled  to  bridge  between 
the  adjoining  ties,  thereby  doubling  the  span  and  in- 
viting a  long  dish  in  the  rail  that  the  angle  bar  can  but 
poorly  prevent,  having  no  support  and  virtually  carrying 
the  tie  that  should  uphold  it. 

The  fishplate  lends  very  little  vertical  support,  so  that 
the  tie  should  be  placed  as  in  Fig.  5-B,  which  you  will 
note  is  the  contrary  to  the  position  used  for  angle  bars. 

However,  the  lateral  support,  or  resistance  to  the  side 
motion  or  spreading  of  the  rails,  which  is  contributed  by 
both  the  angle  bar  and  fishplate  must  not  be_  ignored. 
The  four  spikes  required  for  one  joint  where  the  rails  are 
butted  together,  are  not  only  very  independable  in  main- 
taining the  alignment  but  soon  destroy  the  tie. 

While  the  foregoing  may  appear  to  be  a  needless  explana- 
tion of  self-evident  facts,  it  is  none  the  less  true  that  this 
matter  is  often  suffered  to  go  by  default.  At  some  mines 
where  angle  bars  are  used  great  pains  are  taken  to  insert 
a  tie  directly  under  the  joint  spanned  by  the  angle  bar, 
and  any  good  effects  expected  to  accrue  from  the  use  of  this 
type  of  rail  connection  are  thereby  lost. 

TIE-PLATES  AND   RAIL  BRACES 

Tie-plates  and  rail  braces  have  had  a  restricted  use 
on  mine  tracks,  although  there  are  many  locations  where 
they  might  be  employed  profitably. 

Frequently  the   flange  of  the  rail   wears  to  a  paper- 


28  MINE  TRACKS 

edge  and  the  rail  must  be  removed,  although  the  head 
may  be  but  little  worn.  This  is  due  to  particles  of  grit 
which  intrude  between  the  rail  and  the  tie.  By  observing 
a  train  of  mine  cars  being  drawn  by  a  locomotive,  a  con- 
siderable side  motion  will  be  perceived.  This  side  motion 
tends  to  force  the  rails  outward  as  each  car  passes,  the 
elasticity  of  the  rails  returning  them  to  their  original 
position.  In  time,  a  groove  is  worn  in  the  spike,  allowing 
a  still  greater  motion  to  the  rail,  and  when  grit  accumulates 
under  the  flange  the  rubbing  of  the  rail  on  the  grit  grinds 
away  the  flange. 

The  use  of  tie-plates,  which,  in  their  simplest  form, 
are  merely  plates  provided  with  spike  holes  and  an  offset 
that  resists  the  lateral  thrust  of  the  rail,  prevents  this 
motion  and  consequently  the  wearing  away  of  the  flange. 
The  tie-plate  holds  the  spikes,  so  that  to  obtain  any  side 
motion  it  would  be  necessary  to  force  both  spikes,  while 
the  offset  in  the  plate  prevents  cutting  the  groove  in  the 
spike.  The  tie-plates  purchased  from  a  manufacturer 
are  further  strengthened  by  having  the  bottom  cut  or 
serrated  so  as  to  resist  any  sliding  motion. 

The  tie-plate  can  also  be  used  to  advantage  on  track 
where  the  heavy  traffic  forces  the  rail  into  the  tie  which 
at  intervals  compels  adzing  the  tie  to  give  the  rail  a  true 
bearing.  The  cutting  of  the  rail  into  the  wood  soon 
destroys  the  tie. 

The  amount  of  labor,  taken  in  conjunction  with  the 
cost  of  the  tie,  the  preservation  of  the  rail  achieved  and 
the  inconvenience  entailed  in  doing  this  work,  and  opera- 
ting upon  a  defective  support,  will  afford  a  figure  from 
which  may  be  judged  when  and  where  tie-plates  are  an 
economy.  It  must  also  be  remembered  that  the  plate, 
properly  handled,  should  last  indefinitely. 


TIES  29 

The  application  of  rail  braces  should  be  limited  to 
those  curves  that  are  difficult  to  maintain  in  gage.  The 
braces  prevent  the  tipping  and  the  spreading  of  the  rails 
and  protect  the  tie.  It  should  not  be  necessary  to  use 
both  tie-plate  and  rail  braces  on  the  one  location. 

ROADBED  AND  BALLAST 

The  best  ballast  that  can  be  procured  will  be  of  little 
avail  if  not  properly  tamped.  If  a  tie  is  unsupported, 
it  is  but  an  added  weight  on  the  rail.  The  materials 
in  general  use  for  mine-track  ballast  are  cinders,  slate 
or  vein  refuse,  slate  from  the  breakers  and  broken  rock. 

The  broken  rock  affords  the  best  drainage  and  service, 
but  on  account  of  its  high  cost  is  little  used  for  ballast 
around  surface  mine  tracks.  In  tunnels  and  rock  head- 
ings or  gangways  the  smaller  rock  made  when  excavat- 
ing is  sometimes  thrown  to  one  side  to  be  used  as  ballast. 
Any  lump  should  be  broken  to  a  size  that  would  pass 
through  a  3-in.  ring.  Where  there  is  much  passage  of 
men  and  mules,  the  track  should  be  given  a  light  surfacing 
of  ashes.  The  material  usually  employed  for  ballast  is 
cinders.  It  is  generally  procured  readily  from  the  colliery 
boiler  plant  and  affords  fair  drainage  and  a  fair  degree  of 
service.  The  ashes,  if  kept  in  close  contact  with  the 
rail,  will  hasten  its  corrosion. 

The  refuse  from  the  beds,  or  veins,  is  almost  with- 
out exception  of  a  friable  nature  and  disintegrates  rapidly, 
forming  dust  or  mud.  It  affords  poor  drainage  and  is 
easily  washed  from  the  roadbed.  If  dry,  the  passage  of  the 
cars  swirls  the  refuse  into  the  journals  of  the  car  and  dries 
up  the  lubrication.  It  becomes  mixed  with  the  coal,  and 
in  bituminous  mines  would  be  a  factor  in  a  dust  explosion. 


30  MINE  TRACKS 

Altogether,  it  is  short-sighted  economy  to  use  this  material 
for  ballast. 

Breaker  slate  is  sometimes  used  for  ballast.  It  affords 
a  fair  roadbed  until  it  disintegrates  and  becomes  dust 
or  mud.  Coal  is  a  very  expensive  and  inefficient  ballast. 

Where  practicable,  there  should  be  at  least  3  in.  of 
ballast  beneath  the  ties;  it  should  be  well  tamped,  particu- 
larly under  the  portion  of  the  tie  supporting  the  rail. 
The  ditch  should  be  sufficiently  deep  to  drain  the  road- 
bed and  thereby  assist  in  preventing  the  decay  of  the 
ties.  The  drainage  ditch  should  be  driven  with  the 
heading,  where  necessary,  and  maintained  clear  of  obstruc- 
tions or  accumulations. 

As  it  is  quite  difficult  to  secure  a  good  roadbed,  or 
track,  where  this  is  a  part  of  the  work  of  the  miner  driving 
the  opening,  and  since  it  is  inconvenient  to  furnish  proper 
ballast  to  supply  his  immediate  needs  as  he  advances,  it 
will  usually  be  found  advisable  for  the  trackman  to  go  over 
the  completed  work  at  intervals. 


CHAPTER  III 
PROJECTION  OF  HAULAGE  ROADS 

Where  the  pitch  of  coal  measures  is  heavy,  the  haulage- 
ways  are  driven  to  follow  along  either  the  top  or  bottom 
slate  of  the  bed  at  a  grade  sufficient  to  afford  good  drainage 
or  balance  the  drawbar  pull  on  the  empty  and  loaded  cars. 
When  the  pitch  is  flat,  the  entire  mine  is  projected  and 
developed  along  definite  lines.  In  light,  rolling  pitches, 
the  problem  is  more  complex,  compelling  a  use  of  both  the 
grade  and  projection  methods,  and  frequently  where  there  is 
more  than  one  bed,  a  close  adherence  to  the  lines  of  any  past 
workings. 

As  the  track  must  conform  to  the  headings  or  gang- 
ways as  they  have  been  driven,  some  system  must  be 
employed  in  order  to  have  them  driven  symmetrically. 

In  the  heavy  pitching  beds,  if  the  top  or  bottom  rock 
is  followed  too  closely,  many  irregularities  and  sharp  turns 
will  ensue.  To  preclude  this,  a  definite  minimum  radius 
curve  must  be  adopted  and  a  simple  method  to  attain  this 
established,  which  the  miner  can  understand  and  use 
conveniently. 

Where  there  is  "  double  timber"  or  props  at  regular 
intervals,  what  is  known  as  the  "  chord-offset"  method 
will  be  found  useful.  The  offset  or  distance  in  the  dark 
for  any  set  is  ascertained  by  squaring  the  established 

31 


32 


MINE  TRACKS 


distance  between  the  centers  of  sets  of  props  and  dividing 
by    the    radius.     Let 

D  =  Offset,  or  distance  in  the  dark  in  feet; 

C  =  Distance  in  feet,  center  to  center  of  props ; 

R  =  Radius  of  the  curve; 


then 


FIG.  6. — Method  of  driving  curves  by  offsetting. 


D  =       (see  Fig.  6) 


In  the  case  of  a  40-ft.  radius  curve,  a  rib  radius  of  35 
ft.  and  timber  placed  5  ft.  between  centers,  substituting 
we  have 

OK  C 

D-g -!?/«.,  or  8^ »'n. 


PROJECTION  OF  HAULAGE  ROADS 


33 


Any  two  timbers  in  line  on  the  gangway  are  then  taken, 
and  at  a  point  5  ft.  from  the  proposed  point  of  curve  a 
prop  is  placed  4J£  in.  (one-half  of  8J^  m-)  out  of  line  of 
the  aforesaid  two  sets.  Then  the  prop  just  erected  is 
used  to  line  with  the  prop  at  the  point  of  curve,  and  the 


Top  Split  Gangway 


„      D 


fvN® 

ftiJw\  . 


5o'fad.--fl-c  j£' 


1 


27 


!/x 

4'iM// 

?\  B  Y--50'&d 

'»  •        il 

,v.^,  t».      1 
v  v  ««  \  il    ^  ^  i  ^ 

_|f/^i!=i 

U« r;'-r 


Haulageway 


26-27  25?°I5  for  116-0 
FIG.  7. — Lines  of  sight  and  offsets  for  driving  curves. 


next  is  offset  S^i  in.;  and  so  on,  8>^  in.  on  all  subsequent 
props  until  the  desired  curve  is  completed. 

In  the  event  that  no  timber  is  being  used,  the  same 
results  can  be  attained  by  driving  points  on  line  at  definite 
intervals  in  the  ties  or  roof,  C  is  then  made  the  distance 


34  MINE  TRACKS 

between  the  points,  R  is  the  radius  intended,  and  D  is  the 
offset  distance,  the  first  offset  being  but  half  the  regular 
offset. 

Where  the  headings  or  tunnels  are  driven  on  transit 
lines,  offsets  are  taken  at  from  5  to  10  ft.  from  the  line 
for  any  curves.  Fig.  7  shows  a  typical  plan  for  driving 
by  this  method,  which  is  preferred  for  long  or  large  radius 
curves. 

It  will  be  noticed  that  the  lines  overlap.  This  permits 
setting  up  the  transit  a  convenient  distance  from  the 
working  face,  so  as  not  to  interfere  with  the  work.  The 
heading  is  at  no  time  without  line.  A  few  days  are  allowed 
for  any  delay  arising  in  the  establishment  of  new  lines,  and 
the  points  are  at  a  safe  distance  from  the  blasting  at  the 
face. 

TO  DETERMINE  THE  MOST  ECONOMIC  RADIUS  CURVE  TO 
USE  UNDERGROUND 

To  assist  in  attaining  the  best  possible  track  layout 
underground  consistent  with  the  expenditure  entailed, 
the  conditions  governing  the  radius  of  the  curve  should  be 
analyzed  before  any  standard  radius  is  adopted. 

On  account  of  the  high  cost  of  turning  curves,  the  ad- 
ditional time  it  would  take  to  drive  those  of  large  radii 
and  the  amount  of  the  product  necessarily  tied  up  by 
large  curves,  the  radii  must  be  much  shorter  than  those 
permissible  on  the  surface.  However,  there  is  no  reason 
in  installing  the  smallest  curve  that  cars  will  travel  around 
without  the  bumpers  interlocking,  merely  because  the  initial 
cost  is  low. 

An  ideal  curve  would  be  one  with  which  the  sum  of 
(1)  the  initial  cost,  (2)  the  maintenance  during  the  life  of 
the  curve  and  (3)  the  expense  of  traffic  haulage  will  be  a 


PROJECTION  OF  HAULAGE  ROADS  35 

minimum.  The  consummation  of  this  ideal  can  be  ap- 
proached only  by  assuming  curves  of  various  radii  and 
estimating  the  costs  of  the  several  items. 

Unless  occurring  at  a  site  where  the  roof  is  poor  or 
the  bottom  heaves,  the  shorter  the  curve  the  lower  will  be 
the  initial  expenditure.  In  estimating  the  cost  of  curves, 
certainly,  on  the  shorter  ones  the  cost  of  the  gangway 
or  tunnel  required  to  reach  the  point  attained  by  the  larger 
curves  should  be  considered,  particularly  as  it  is  customary 
to  leave  considerable  pillar  each  side  of  a  tunnel  or  main 
heading.  When  turning  curves  of  large  radii,  the  wide 
part  of  the  opening  just  beyond  the  frog  can  sometimes  in 
the  heavy  pitches  be  located  in  solid  rock,  thereby  dispens- 
ing with  the  use  of  timber  and  obviating  any  allowance  for 
maintenance. 

As  the  life  of  curves  is  frequently  over  30  years,  and 
wood  timber  has  a  serviceableness  as  low  as  18  months, 
the  items  of  labor  and  material  for  timber  removals,  in 
addition  to  the  risk  of  a  derailed  car  knocking  down  the 
roof  supports,  with  the  delays  in  traffic  incident  to  retimber- 
ing,  must  be  thoroughly  considered.  The  use  of  steel 
timber  will  be  found  advantageous  for  the  long  spans 
encountered  at  locations  where  a  semipermanent  job  is 
required  and  no  "heaving"  or  "squeezing"  is  to  be 
expected. 

In  turning  off  tunnels  where  several  beds  to  be  worked 
lie  close  together,  a  lower  upkeep  will  be  realized  by  a 
"  wing"  tunnel  to  the  outer  bed  and  continuing  on  the  same 
line  to  the  inner  ones,  than  by  having  a  number  of  wide 
areas  to  maintain  from  a  number  of  curves  off  the  main 
haulageway.  This  also  forestalls  the  cramping  of  the 
switchwork  and  radii,  which  closely  situated  veins  ordinarily 
demand. 


36  MINE  TRACKS 

Viewed  solely  from  the  haulage  standpoint,  the  determin- 
ing factors  of  the  curve  radius  can  be  covered  under  two 
heads:  (1)  The  cost  of  resistance  due  to  curvature  on  the 
total  estimated  number  of  cars  to  be  hauled;  (2)  the  probable 
number  of  cars  to  be  hauled  in  each  trip  and  the  rate  of 
travel. 

The  amount  of  resistance  due  to  curvature  varies  with 
each  type  of  car,  and  to  a  lesser  degree  with  each  car  of  a 
given  type.  The  resistance  expressed  in  terms  of  grade 
with  curves  of  from  30-  to  100-ft.  radius,  42-in.  gage,  42-in. 
wheelbase,  will  run  0.015  ft.  to  0.025  ft.  per  100  ft.  of 
track  for  each  degree  of  curvature.  That  is,  with  a  50-ft. 
radius  or  a  115-deg.  curve,  moderately  clean  track,  fair 
running  cars  with  both  wheels  keyed  to  the  axle,  approxi- 
mately a  1.8  per  cent,  grade  would  be  necessary  to  equal  the 
same  drawbar  pull  as  on  a  tangent.  A  smaller  com- 
pensation would  be  sufficient  where  the  wheels  turn  loose 
on  the  axles  and  the  wheelbase  is  less. 

The  value  of  the  radius  expressed  in  degrees  can  be 
obtained  by  dividing  5730  by  the  radius  in  feet.  This 
formula  will  have  to  be  employed  especially  in  small 
radius  curves.  The  actual  arc  is  used  to  find  the  degree, 
rather  than  the  100-ft.  chord,  the  practice  on  standard- 
gage  roads.  By  using  the  actual  arc,  a  50-ft.  radius  = 

,n    =  115-deg.  curve.     By  the  use  of  the  100-ft.  chord, 
ou 

a    50-ft.    radius  =  —  —  ^7    =  180-deg.    curve,   showing   a 


disparity  of  65  deg. 

Assuming  a  curve  with  a  central  angle  of  90  deg.  on 
a  grade  of  0.5  per  cent,  and  allowing  the  same  rate  of 
resistance  per  degree  on  a  25-ft.  and  50-ft.  radius 
curve,  the  motor  traveling  over  them  would  have  to 


PROJECTION  OF  HAULAGE  ROADS  37 

mount  the  sum  of  the  grade  and  the  curve  resistance, 
the  equivalent  of  a  4.5  per  cent,  grade  for  39  ft.  and  a  2.5 
per  cent,  grade  for  78  ft.  respectively.  From  the  be- 
ginning of  the  50-ft.  radius  to  the  point  of  tangency, 
there  would  be  with  the  curve  resistance  the  equivalent 
of  1.96  ft.  vertical,  while  to  travel  between  the  same 
points  by  way  of  the  25-ft.  radius  curve,  including  the 
25  ft.  of  tangent  on  each  end  of  the  curve  to  reach  the 
same  geographical  point,  would  be  a  total  of  2.02  ft. 
vertical,  or  essentially  the  same  vertical  rise  in  both  cases. 

While  actually  with  the  smaller  radius  curve  there  would 
be  a  lower  rate  of  resistance  per  degree,  this  would  be  more 
than  balanced  by  the  increased  resistance  due  to  the  slower 
speed  compelled  by  the  sharper  curve.  If  the  resistance 
due  to  grade  and  curvature  between  the  similarly  located 
points  is  accepted  as  equal,  then  there  remains  in  favor 
of  the  50-ft.  radius  the  greater  speed  at  which  the  trip 
can  travel,  the  reduced  danger  of  cars  jumping  the  track, 
the  greater  ease  with  which  the  trolley  will  follow  the  wire, 
a  haul  11  ft.  shorter,  and  in  some  cases  11  ft.  less  of  tunnel. 
With  a  heading  producing  six  trips  per  day  of  twelve  5-ton 
cars  each,  this  11  ft.  twice  per  trip  would  consume  enough 
power  to  draw  one  ton  7920  ft.  each  day,  or  375  miles  per 
year. 

In  estimating  the  number  of  cars  per  trip,  the  future 
output,  as  well  as  the  length  of  haul,  must  be  considered. 
The  number  of  cars  traveling  over  a  certain  haulage  road 
daily  may  sometimes  be  trebled  by  a  tunnel  to  other  beds. 

This  increased  output  may  mean  the  installation  of  a 
larger,  or  possibly  the  use  of  an  additional,  locomotive. 
If  the  curves  are  too  sharp,  the  larger  machine  cannot 
traverse  them,  and  this  leaves  no  choice  but  the  additional 
motor  with  its  expense  for  attendance  and  upkeep. 


38  MINE  TRACKS 

For  obvious  reasons  no  compensation  is  allowed  for 
curvature  underground,  and  if  a  locomotive  is  required 
to  work  at  its  capacity,  the  additional  resistance  to  be 
overcome  due  to  curvature  may  be  the  factor  limiting 
the  length  of  the  trip.  With  the  large  curve  a  locomotive 
may  pull  through  on  its  momentum,  but  on  a  curve  of 
small  radius  the  velocity  must  be  reduced  when  the  curve  is 
approached. 

ALIGNMENT  ON  THE  SURFACE 

The  general  practice  in  the  location  of  narrow-gage 
railroads  on  the  surface  is  to  first  run  a  topography  survey 
and  then  plot  this  to  a  suitable  scale.  If  the  relative  posi- 
tion and  elevation  of  both  the  beginning  and  destination 
of  the  proposed  road  are  known,  it  may  be  found  practicable 
to  run  a  rough  grade  line  between  them.  Using  this  as  a 
base,  enough  of  the  surface  features  on  each  side  may  be 
located  to  permit  any  desired  deviation  from  the  original 
base  line.  Sufficient  accuracy  is  usually  attained  by  using 
circle  levels  taken  with  a  transit  to  the  objects  and  ground 
to  be  located,  and  only  in  special  cases  need  the  topography 
be  located  with  a  wye  level  or  Locke  level. 

When  the  location  has  been  plotted  and  any  outcroppings 
of  veins  and  other  influencing  features  shown,  the  proposed 
line  is  laid  out  on  paper  and  submitted  for  approval. 

This  approval,  however,  in  the  case  of  narrow-gage  mine 
roads,  is  usually  permission  to  use  a  certain  maximum  and 
ruling  grade,  and  the  adoption  in  general  of  the  layout. 
It  is  not  intended  that  the  layout  be  adhered  to  rigidly, 
and  the  engineer  is  permitted  to  use  his  judgment  in  making 
any  minor  changes  in  the  grade  or  route. 

It  is  ail  infrequent  occurrence  that  the  mine  track  leaves 
the  company's  lands,  and  no  right-of-way  is  required. 


PROJECTION  OF  HAULAGE  ROADS 


39 


These  facts  and  the  comparative  flexibility  of  the  narrow- 
gage  road,  with  its  almost  unlimited  allowance  in  curvature, 
render  the  field  work  for  a  narrow-gage  road  a  comparatively 
simple  matter. 

As  this  work  is  usually  assigned  to  the  regular  mine 
engineer  corps,  which  frequently  is  not  particularly  familiar 
with  it,  the  customary  methods  pursued  are  given. 


FIG.  8. — Method  employed  in  locating  a  curve  on  the  surface. 

One  practice  in  some  use  is  to  scale  the  location  from 
the  plan  and  then  duplicate  it  in  the  field.  Because  of 
possible  inaccuracies  in  the  preliminary  survey,  the  pos- 
sible divergence  of  the  approved  location  from  the  base 
line,  and  the  errors  in  scaling  it,  this  method  is  not  to  be 
recommended. 


40  MINE  TRACKS 

A  preferable  way  is  to  place  stakes  on  grade  at  50-  to 
100-ft.  intervals,  depending  on  the  nature  of  the  ground, 
and  then  use  these  stakes  as  a  guide  in  selecting  the  straight 
track  or  tangents.  The  radius  of  a  curve  is  partly  deter- 
mined by  establishing  the  point  of  intersection  and  measur- 
ing the  distance  from  this  point  to  where  it  is  desired  to 
locate  the  line  of  curve  (see  Fig.  8). 

The  radius  required  is  found  by  the  formula, 

Distance  measured 
Radius  =  -         —. f-/ —  — r* 

exl.-sec  >-2  central  angle 

If  the  country  is  heavily  wooded  and  the  tangents 
cannot  be  selected  readily  in  the  field,  the  grade  stakes 
should  be  located  and  plotted  and  the  line  chosen.  The 
tangents  are  then  established  in  the  field  by  measure- 
ments from  the  stakes  and  the  intersection  and  curves  run  in. 

The  prime  consideration  in  most  mine  roads  is  to  have 
the  grading  and  excavating  a  minimum;  this,  of  course, 
can  best  be  accomplished  by  the  use  of  grade  stakes. 

In  standard-gage  practice,  a  1-deg.  curve  is  one  on  which 
a  100-ft.  chord  will  subtend  a  central  angle  of  1  deg. ;  a  2-deg. 
curve,  a  central  angle  of  2  deg.  with  a  100-ft.  chord;  a  3-deg. 
curve,  a  central  angle  of  3  deg.  with  a  100-ft.  chord,  and  so 
on,  the  radius  being  calculated  by  trigonometry  from  the 
degree  and  chord.  The  curve  is  easily  laid  out  by  deflection 
angles  and  100-ft.  chords. 

In  computing  the  various  parjbs  of  a  curve,  the  following 
formula  will  cover  most  cases  (see  Fig.  8). 

R  =  Radius  of  curve, 
D  =  Degree  of  curve, 

T  —  Tangent  distance, 

E  =  External  distance, 

A  —  Angle  subtending  chord  or  sub-chord, 
A  =  Central  angle. 


PROJECTION  OF  HAULAGE  ROADS  41 

(1)  External  angle  =  central  angle;  the  external  angle 
is  that  one  measured  by  the  transit  upon  the  intersection 

of  the  tangents. 

pi 

(2)  Radius  =  ^  ^     ,  l/    ,  E  is  found   as   described 
above. 

(3)  Sin   Y^D  =  ~n,  the  angle  corresponding  to  sin  ^D 

can  then  be  found  in  a  table  of  natural  sines  and  cosines, 
and  doubling  this  angle  will  give  the  degree  of  the  curve. 
(See  pages  43  and  88  for  short  radii  formula.) 

(4)  Tangent  =  R  X  tan  %A;  when  the  radius  is  known, 
before  the  curve  can  be  staked  out,  it  is  necessary  to 
know   the    p.c.    or    point   where    the    curve   commences. 
When  this  is  found,  the  tangent  distance  is  measured  from 
the  point  of  intersection,  and  will  locate  the  p.c.;  measuring 
the  same  distance  on  the  line  of  the  other  tangent  will 
establish  the  p.t.,  the  end  of  curve,  or  point  of  tangent. 

t 

(5)  Radius  =  to  i/^'     H»    frequently     happens    that 

the  point  of  curve  must  be  located  at  a  certain  definite 
point,  as  at  the  end  of  a  bridge  or  switch.  The  tangent 
distance  is  then  measured  and  the  proper  radius  of  the 
curve  calculated  from  this  formula. 

(6)  The   deflection   angle  for  a   100-ft.   chord   is    one- 
half  the  degree  of  curvature. 

(7)  If  there  is  no  table  of  external  secants  convenient, 
use  a  table  of  natural  sines  and  cosines,  and  divide  the 
cosine  of  one-half  the  central  angle  into  1,  and  then  sub- 
tract 1  from  the  result;  this  will  be  the  external  secant. 
For  example,  if  one-half  the  central  angle  is  18  deg.,  the 
cosine  is  0.9511;  dividing  this  into  1  gives  1.05146,  and 
subtracting  1,  we  have  0.05146,  the  external  secant. 


42  MINE  TRACKS 

(8)  When  the  curve  is  to  be  staked  out  at  less  than  100  -ft. 
intervals,  as  is  the  case  in  narrow-gage  work,  sub-chords 
must  be  used.  The  angle  for  the  sub-chord  deflection  is 

.      ,    ,       ,  ,      f         ,  ,  .  .       sub-chord 

determined   by  the  formula  sin   J%4  =  -    —^  ---     The 

2/t/ 


angle  corresponding  to  sin  %A  will  be  found  in  a  table  of 
natural  sines. 

If  the  angle  is  known,  as  is  the  case  with  the  last  deflec- 
tion for  a  curve,  the  formula  becomes,  %  sub-chord  =  R 
sin  J^A. 

The  deflection  angle  for  any  chord  is  always  equal  to 
one-half  the  central  angle  subtending  it.  For  100-ft. 
chords,  the  deflection  angle  would  be  one-half  the  degree 
of  curve.  In  formula  8  the  angle  equivalent  to  sin  ^A 
would  be  the  correct  one  to  turn  for  the  proposed  sub-chord. 

When  the  radius  of  the  curve  has  been  determined  and 
the  p.c.  (point  of  curve)  exactly  located,  the  distance  is 
measured  from  the  last  numbered  stake  to  the  p.c.  The 
stake  here  located  is  numbered,  and  the  transit  set  up  over 
it.  If  the  p.c.  is  not  at  the  end  of  an  even  chord  length, 
it  will  be  necessary  to  work  out  the  deflection  for  the  sub- 
chord,  as  shown  under  formula  7. 

The  p.c.  is  the  point  of  curve  in  the  direction  the  survey 
is  being  run,  and  the  p.t.  (point  of  tangent)  the  end  of  the 
curve. 

The  first  deflection  from  the  p.c.  will  be  the  angle  J^Z) 
from  the  tangent  line  for  the  distance  of  the  chord.  If 
the  second  stake  on  the  curve  can  be  put  in  from  the  p.c., 
the  angle  required  is  added  to  the  first  angle  and  turned  from 
the  p.c.  The  distance,  however,  is  measured  from  the  last 
stake.  This  process  continues  as  far  ais  can  be  staked  out 
from  the  p.c.,  or  until  the  p.t.  is  reached.  The  deflection 
angles  should  be  added  until  they  equal  one-half  the  central 


PROJECTION  OF  HAULAGE  ROADS  43 

angle,  which  should  intersect  the  p.t.,  if  the  work  has  been 
done  correctly.  The  measurements  are  taken  each  time 
from  the  last  stake. 

If  it  is  impossible  to  see  from  the  p.c.  to  the  p.t.  and  all 
the  intermediate  points,  the  transit  can  be  set  on  any  in- 
termediate stake  and  the  curve  continued  therefrom.  When 
the  transit  is  set  up  on  the  curve,  the  vernier  is  set  at  zero, 
backsighted  on  the  last  place  over  which  the  transit  was 
set  up  and  the  telescope  reversed.  By  turning  the  vernier 
to  the  last  angle  turned,  the  line  will  be  tangent  to  the  curve 
at  the  set-up,  and  deflection  angles  can  again  be  added  until 
the  p.t.  is  reached.  The  transit  should  then  be  set  up  on 
the  p.t.  and  can  be  again  turned  tangent  by  reversing  the 
telescope  and  turning  the  last  angle.  The  sum  of  the  de- 
flection angles  must  equal  one-half  the  central  angle,  and 
with  the  angles  turned  upon  backsighting,  equal  the  total 
central  angle.  The  chords  are  always  measured  from  stake 
to  stake,  as  shown  in  Fig.  8,  from  p.c.  to  a,  from  a  to  b, 
b  to  c,  etc. 

In  all  American  handbooks  for  standard-gage  track, 
and  in  formula  3  of  the  foregoing,  all  calculations,  degrees 
of  curve,  etc.,  are  based  on  the  underlying  principle  that  a 
100-ft.  chord  determines  the  degree  of  curve. 

It  is  obvious  that  it  is  not  very  convenient  to  use  this 
100-ft.  chord  method  with  short-radii  curves,  and  it  is 
mathematically  impossible  to  use  it  with  curves  of  less  than 
50-ft.  radius,  as  will  be  seen  by  formula  3. 

Many  engineers  have  resorted  to  computing  short  tables 
for  their  own  use  for  this  class  of  work,  but  the  majority  of 
such  tables  are  decidedly  incomplete. 

If  we  assume,  however,  for  the  shorter-radius  curve  that 
a  1-deg.  curve  is  one  in  which  a  10-ft.  chord  subtends  a 
1-degree  central  angle,  all  the  numerous  labor-saving  tables 


44  MINE  TRACKS 

developed  in  the  standard  fieldbooks  can  be  adopted  and 
applied  to  this  work  by  merely  moving  the  decimal  point 
mentally  one  place. 

For  example. — A  1-deg.  curve  would  then  have  a  573-ft. 
radius  instead  of  a  5730-ft.  radius;  the  long  chords,  externals, 
tangent  distances,  etc.,  would  be  one-tenth  as  great.  The 
angle,  of  course,  would  not  change. 

If  a  10-ft.  chord  was  thought  too  short  for  use,  the 
long  chord  for  two  stations  (or  three  stations,  as  desired) 
would  be  taken  from  the  tables. 

Or  if  no  standard  fieldbook  is  at  hand,  the  foregoing  for- 
mulae may  be  used  without  any  change  with  the  exception 
of  formula  3,  which  would,  on  the  10-ft.  chord  basis,  be 

sin 

The  table  entitled  "  Radii,  Degrees  of  Curve  and  Ordi- 
nates,"  appearing  later,  gives  degrees  of  curve  on  this 
method  for  radii  from  15  to  200  feet. 

It  will  be  found  convenient  in  most  cases,  when  the 
radius  on  either  the  100-ft.  or  10-ft.  chord  plan  corre- 
sponds to  a  fractional  degree  of  curvature,  to  take  the 
nearest  degree  and  change  the  radius  to  agree  therewith. 
For  example,  if  the  radius  corresponded  to  9  deg.  43  min., 
it  will  simplify  the  field  work  usually  to  make  it  a  10-deg. 
curve,  and  alter  the  radius,  etc.,  correspondingly. 


CHAPTER  IV 
GRADES 

In  railroad  work  the  number  of  feet  of  rise  or  fall  per 
unit  of  distance  is  called  the  grade;  the  number  of  feet  of 
rise  or  fall  per  100  ft.  horizontal,  the  per  cent,  of  grade. 

On  the  surface  the  grade  for  locomotive  traffic  is  de- 
termined, first,  by  the  size  of  the  locomotive  and  the  number 
of  cars  it  is  required  to  haul;  second,  by  the  elevation  it  is 
desired  to  attain  in  a  certain  distance;  and  third,  by  the 
topography  of  the  route. 

Underground,  where  the  headings  are  driven  on  line, 
the  grade  follows  the  pitch  of  the  heading,  rope  haulage 
and  planes  being  introduced  when  the  grade  becomes 
too  heavy  for  locomotive  traffic. 

On  the  heavier  pitching  measures  the  gangways  are 
usually  driven  on  a  regular  grade,  which  follows  the  strike 
of  the  bed.  In  determining  this  grade,  the  drainage, 
haulage,  and  to  a  certain  extent  the  loading  of  the  cars, 
should  be  considered. 

In  lightly  pitching  or  rolling  measures,  before  any 
lines  for  headings  or  chambers  are  adopted,  the  probable 
contours  of  the  bed  should  be  shown  in  advance  of  the 
workings,  so  that  an  idea  of  the  grade  that  is  likely  to  be 
encountered  may  be  formed.  A  study  of  the  contours  and 
close  attention  to  the  grade  as  the  heading  advances  will 
serve  to  forestall  using  the  heavier  grades  requiring  rope 

45 


46  MINE  TRACKS 

haulage  or  the  employment  of  other  forms  of  haulage  than 
locomotives  or  mules. 

A  specific  grade  cannot  be  adhered  to  rigidly  in  the  light 
pitching  or  so-called  flat  measures,  but  nevertheless  more 
attention  should  be  given  to  approximating  this  grade. 
Too  often  the  workings  are  projected  with  very  little 
consideration  toward  anything  other  than  releasing  a 
certain  area  of  coal,  the  lines  being  followed  regardless  of 
the  grade.  This  enta'ils  high  transportation  costs.  A 
combination  of  the  line  and  contour  method,  while  affording 
a  less  symmetrical  layout,  secures  a  more  economic  haulage. 

A  good  rule,  applicable  in  many  cases  where  headings 
are  driven  by  alignment,  is  to  first  determine  the  lines 
as  far  as  practicable  to  conform  with  both  the  area  to 
be  worked  and  the  best  possible  grade,  then  to  establish 
a  maximum  grade  and  give  each  line  with  the  under- 
standing that  this  line  shall  be  followed  only  so  long  as 
the  inclination  of  the  strata  does  not  compel  exceeding 
this  grade.  Should  this  inclination  be  encountered,  fur- 
ther advices  can  be  then  given,  based  on  the  latest  de- 
velopments, before  the  heading  is  continued. 

In  the  determination  of  a  standard  gangway  grade 
for  the  gangways  in  the  heavier  pitching  beds,  the  first 
requisite  should  be  that  the  grade  be  sufficient  to  take  care 
of  the  drainage  and  allow  the  water  to  maintain  its  channel 
free  from  any  accumulations  of  silt  or  sediment.  Good 
drainage  is  a  requirement  in  any  type  of  haulage,  and  in 
the  maintenance  of  the  ballast  and  trackwork  it  is  a 
necessity. 

A  ditch  with  a  semicircular  cross-section  will  have 
the  greatest  carrying  capacity,  while  one  with  a  half- 
hexagon  cross-section  is  the  nearest  practical  approach 
thereto  for  mine  work. 


GRADES 


47 


The  following  is  an  approximation  of  Cutters'  formula 
for  ditches, 


/ 100,000  r*s 
~~^1    8r+15 


in  which 


V  =  Mean  velocity  per  second; 

r—  Hydraulic  radius;  that  is,  the  cross-section  of  the 
water  in  the  ditch  in  feet,  divided  by  the  perimeter 
of  the  ditch  in  contact  with  the  water; 

s  =  The  slope;  that  is,  the  fall  divided  by  the  length. 


FIG.  9. — Practical  drainage  ditch. 

The  following  table  shows  the  carrying  capacity  and 
mean  velocity  for  a  ditch  with  a  half-hexagon  cross-sec- 
tion per  foot  of  bottom  width.  (See  Fig.  9.) 


Grade    per 
100  feet 

Mean  velocity  in 
feet   per  second 

Cubic  feet 
per  second 

Cubic  feet 
per  minute 

Gallons    per 
minute 

4  in  

1.84 

2.39 

143  5 

1,075 

6  in  

2.25 

2  92 

175  5 

1,315 

8  in  
10  in  

2.60 
2.90 

3.38 
3.78 

202.5 
226  8 

1,520 
1,700 

12  in  

3.19 

4  14 

248  4 

1,863 

A  wide,  shallow  ditch  with  the  same  cross-sectional 
area  and  grade  will  have  less  current  velocity,  will  carry 
less  water,  and  will  choke  up  much  more  easily  than  one 
of  a  narrower  and  deeper  form.  The  velocity  should  not 


48  MINE  TRACKS 

be  less  than  1J^  ft.  per  second,  or  the  suspended  particles 
will  be  precipitated  along  the  bottom  of  the  ditch. 

Where  drainage  is  not  the  prime  consideration,  a  theo- 
retic grade  can  be  computed,  whereby  the  slope  of  the 
road  in  favor  of  the  loaded  cars  will  compensate  for  the 
extra  resistance  due  to  the  additional  weight.  In  other 
words,  a  proper  utilization  of  the  grade  will  allow  the 
drawbar  pull  on  a  trip  of  loaded  cars  to  equal  that  of  an 
equal  number  of  empty  cars.  The  motor  or  mules  will 
thus  be  able  to  pull  as  many  cars  from  the  face  loaded  as 
were  brought  in  empty. 

The  prevailing  grade  in  mines  where  it  is  possible  to 
establish  a  grade  with  no  consideration  but  that  of  haul- 
age runs  from  4  in.  to  6  in.  per  100  ft.;  that  is,  a  0.33  per 
cent,  and  0.5  per  cent,  grade  respectively.  Within  the 
last  few  years  it  has  been  realized  that  this  grade  is  rather 
too  light  unless  some  type  of  anti-friction  bearing  is  used. 
Accordingly,  many  companies  have  fixed  their  standard 
gangway  grade  at  from  6  in.  to  10  in.  per  100  ft. 

It  is  obvious  that  the  greater  the  difference  in  weight 
between  an  empty  and  loaded  car,  the  steeper  should  be 
the  grade  in  favor  of  the  load  to  overcome  the  greater 
resistance  due  to  the  load. 

The  amount  of  track  resistance  is  almost  proportional 
to  the  weight  on  the  rails,  and  as  the  modern  practice 
has  been  to  enlarge  the  capacities  of  cars,  the  grade  should 
likewise  be  augmented  following  any  increase  in  car  loading; 
or  the  additional  resistance  from  the  increased  load  should 
be  overcome  by  reducing  the  journal  friction  by  an  improve- 
ment in  the  bearings. 

The  following  example  will  illustrate  the  usual  method 
of  computing  the  theoretic  grade  which  will  equalize  the 
drawbar  pull  on  empty  and  loaded  cars. 


GRADES  49 

Example. — A  certain  colliery  has  in  use  all-steel  cars 
weighing  empty  5080  Ib.  each  and  loaded  with  coal  an  aver- 
age of  12,230  Ib.  As  the  track  is  dirty  and  not  very  well 
laid,  the  total  frictional  resistance  will  be  assumed  as  30 
Ib.  per  ton  for  an  empty  car  and  25  Ib.  per  ton  on  a  loaded 
car;  in  other  words,  the  coefficient  of  friction  (or  ratio  of 
the  resistance  to  the  weight)  will  be  0.015  and  0.0125 
respectively.  It  is  desired  to  find  the  grade  that  will 
equalize  the  draw-bar  pull  on  an  empty  car  with  a  loaded 
car.  Let 

0  =  The    sine    of    the    angle    of    the    desired    grade; 
W  =  Weight  of  empty  car; 
W  =  Weight  of  loaded  car; 
C  =  Coefficient  of  friction  for  empty  car; 
C"  =  Coefficient  of  friction  for  loaded  car; 
then 

(W  C)  +  W  sin  0  =  (W  C')  -  W  sin  0 

Substituting  values  in  the  above  case, 

(5080  X  0.015)  +  5080  sin  0  =  (12,230  X  0.0125)  - 

12,230  sin  0. 

76.2  +  5080  sin  0  =  152.875  -  12,230  sin  0. 
17,310  sin  0  =  76.675, 

sin  0  =  .00443,   . 

which  multiplied  by  100  will  give  the  rise  in  100  ft.,  which 
is  0.443  ft.,  or  5^  in. 

On  straight  track,  with  5J4-in.  grade  per  100  ft.  in  favor 
of  the  load,  a  mule  would  be  able  to  pull  as  many  loaded 
cars  out  as  it  could  pull  empty  cars  in  the  opposite  direction. 
The  preceding  formula  does  not  consider  the  weight 
of  the  motor  or  locomotive,  the  effective  weight  of  which 
will  also  depend  on  the  grade. 

If  in  the  foregoing  example  we  wished  to  use  an  8-ton 


50  MINE  TRACKS 

motor  having  a  tractive  effort  of  3000  Ib.   on  the  level, 
and  secure  an  equal  draw-bar  pull  and  maximum  loading, 
the  formula  will  be  somewhat  different. 
Let 

M  =  Weight  of  motor; 
F  =  Tractive  effort  of  motor. 

Then 

F  +  M  sin  <£  F  -  M  sin  <£ 


(TF'0)  -  W  sin  0     (WC)  +  W sin  0 
Solving, 

0  =  5  in.  per  100  ft. 

With  the  same  motor  compelled  to  handle  cars  loaded 
with  rock,  the  formula  in  order  to  make  the  grade  balance 
the  extra  resistance  of  a  full  trip  of  rock,  the  weight  of  each 
car  being  17,000  Ib.,  would  be,  letting  W"  =  weight  of  a 
loaded  rock  car, 

F  +  Msin<f>  F  -  M  sin  <j> 

(W'C')~-  W"sin<t>~(WC)  +  Wsin<j> 
or 

0  =  7  in.  (almost)  per  100  ft. 

The  grade  on  straight  track  should  then  be  between 
5  and  7  in.  per  100  ft.,  and  the  above  motor  would  be 
able  to  pull  in  about  28  empty  cars  and  the  same  number 
out,  loaded. 

When  it  is  considered  that  curved  track  makes  up  a 
large  portion  of  every  gangway  and  that  the  tracks  are 
dirtiest  immediately  after  the  cars  have  been  loaded  from 
chutes  (all  of  which  has  a  greater  effect  on  the  loaded  car), 
it  will  be  apparent  that  this  theoretic  grade  should  be 
increased  to  assist  in  overcoming  these  contingencies. 

Other  considerations  that  would  still  further  increase 


GRADES  51 

the  grade  in  favor  of  the  load  are  the  usual  methods  pursued 
in  panel  mining  and  the  loading  of  the  cars. 

It  is  customary  in  panel  mining  to  drive  the  coal  gang- 
ways first,  and  when  they  have  advanced  far  enough  to 
begin  robbing,  to  tunnel  to  a  haulage  gangway,  cutting 
off  the  outer  section.  This  frequently  increases  the  length 
of  the  tunnels  and  necessitates  a  proportionate  decrease 
in  the  grade  of  the  haulage.  As  a  consequence,  where  the 
tunnels  are  long,  the  inclination  of  the  haulage  road,  which 
by  all  means  should  have  the  best  grade,  is  much  reduced, 
and  wet  roadbed,  choked  ditch  and  small  trips  naturally 
result. 

Since  the  installation  of  mechanical  haulage  in  mines 
loading  from  chutes,  the  loaders  are  compelled  to  move 
the  cars  at  the  loading  places  by  their  own  efforts.  Four 
cars  per  trip  are  not  infrequently  loaded  from  one  chute. 
On  the  lighter  grades,  to  move  the  cars  sufficiently  to 
accomplish  this  loading  would  require  an  additional  man, 
and  to  forestall  .this  expense  the  foreman  resorts  to  increas- 
ing the  grades  immediately  beneath  the  chutes  and  inserting 
an  equalizing  diminution  between  them.  This  expedient 
facilitates  the  loading  of  the  cars,  but  renders  the  roadbed 
a  succession  of  flat  places  and  inclines,  with  pools  of  water 
in  the  "dead  spots."  It  raises  the  haulage  cost,  destroys 
the  rolling  stock  and  imparts  a  bumping  and  jerking  to  the 
cars  in  motion.  It  is  needless  to  state  that  a  proper  grade 
would  remove  the  necessity  for  this  distortion. 

In  the  gangways  where  the  grades  have  been  produced  by 
trusting  to  the  judgment  of  the  workmen,  the  inclination 
usually  is  from  8  to  12  in.  per  100  ft.,  and  I  am  inclined 
to  believe  that  these  grades  have  more  to  recommend  them 
than  the  lesser  ones. 

One  objection  to  the  heavier  grade  is  that  its  first  in- 


52 


MINE  TRACKS 


jog  MDJQ  spunoj 


GRADES 


53 


54  MINE  TRACKS 

stallation  reduces  the  available  lift  as  the  gangway  ad- 
vances; this,  however,  will  remedy  itself  in  all  subsequent 
levels. 

In  the  case  of  light  pitching  beds,  increasing  the  grade 
of  new  headings  may  mean  a  too  serious  shortening  of  the 
available  lift,  and  in  those  headings  already  driven  the 
flat  grades  will  limit  the  length  of  the  trip. 

These  objections,  as  well  as  that  arising  from  the  necessity 
of  moving  the  cars  while  loading,  can  be  overcome  to  a 
great  extent  by  the  use  of  bearings  that  reduce  the  journal 
friction.  An  improved  type,  such  as  the  Hyatt  roller 
bearing  (as  has  been  demonstrated  by  dynamometer  tests), 
will  require  on  the  level  but  about  40  per  cent,  of  the  draw- 
bar pull  necessary  with  the  common  type  of  bearing,  or 
conversely,  on  the  level  a  motor  will  pull  2^4  times  as 
many  cars  if  they  are  equipped  with  antifriction  bearings 
as  it  will  if  plain  bearings  are  used.  The  accompanying 
charts,  Figs.  10  and  11,  are  from  actual  tests  and  show  the 
draw-bar  pull  of  roller  bearing  and  plain  bearing  cars. 
Both  tests  were  over  the  same  run.  The  low  starting  effort 
required  for  the  improved  bearing  should  be  noted.  The 
grade  formula  will  have  to  be  applied  to  determine  the 
results  for  level  track. 

Substituting  in  the  formula,  and  using  the  same  weights : 

(WC)  +  (W    sin    </>)  =  (W    C")  -  (TF    sin    0) 
(5080  X  0.006)  +  5080  sin  0  =  (12,230  X  0.005)  - 

12,230  sin  <t> 

30.48  +  5080  sin  <f>  =  61.15  -  12,230  sin  </> 
17,310  sin  </>  =  30.67 

Sin  0  =  0.00177.  This  multiplied  by  100,  will  give  the 
per  cent,  of  grade,  which  is  0.177  ft.,  or  2%  inches. 

Thus  with  suitable  antifriction  bearings  it  would  require 


GRADES  55 

on  a  grade  of  2^  in.  per  100  ft.  the  same  effort  to  move  a 
loaded  car  with  the  grade  as  is  required  for  an  empty  car 
moving  against  it. 

The  antifriction  bearing  will  run  several  months  on 
one  lubrication,  thereby  eliminating  to  a  great  extent 
the  embarrassment  of  stiff  cars  and  the  employment  of 
car  oilers.  They  will  be  found  advantageous  in  locations 
where  the  available  elevation  for  compensating  grades  is 
limited  and  in  reducing  the  elevation  required  for  the  car 
planes  in  overcoming  differences  in  grade,  also  on  light 
pitching  slopes  where  the  cars  are  barely  able  to  drag  the 
rope,  and  in  eliminating  men  required  for  pushing  around 
dumps,  shaft  landings,  and  tipples. 

CONSTRUCTING  GRADES 

Grades  on  the  surface  are  secured  by  running  levels  over 
stakes  set  at  regular  intervals  and  then  marking  upon  the 
stakes  the  cuts  or  fills  required  to  reach  the  grade  selected, 
to  which  the  surface  is  then  cut  or  filled. 

In  the  flat  measures  underground,  the  headings  are 
generally  driven  on  line,  the  grade  of  the  heading  being  the 
profile  of  the  bottom  rock  along  the  line  of  heading. 

In  the  gangways  or  headings  which  are  not  driven  on 
line,  it  is  apparent  that  neither  of  the  methods  given 
can  be  used;  by  the  first  method  the  heading  would  have 
to  be  already  driven  before  the  grades  could  be  run  and 
marked;  by  the  second  method  a  line  would  have  to  be 
given,  which,  of  course,  would  be  impossible  in  the  heavy 
pitching  seams. 

Under  this  last  condition,  and  also  for  tunnels,  the 
grade  is  extended  by  means  of  a  grade  board;  that  is,  a 
board  equipped  with  a  spirit  level  set  in  its  top,  or  with  a 
plumb-line  which  hangs  from  an  upright  in  the  center  of  the 
board.  The  grade  is  carried  by  having  one  end  of  the  board 


56 


MINE  TRACKS 


higher  than  the  other,  this  extra  height  being  the  amount 
that  the  grade  in  question  would  rise  or  fall  in  the  length  of 
the  board.  This  extra  height  is  known  as  the  "toe." 

Grade  boards  are  usually  cut  in  fractional  lengths  of 
100  ft.,  such  as  6J4  ft.,  10  ft.,  12^  ft.,  etc.,  so  that  the 
toe  can  be  readily  calculated  and  the  board  will  be  of  a 
length  convenient  for  use.  The  following  table  gives 
the  toes  to  the  nearest  KG  m-  f°r  a  10-ft.  grade  board  on 
grades  from  0  per  cent,  to  10  per  cent. : 
TOES  FOR  10-FT.  GRADE-BOARD  FROM  0  TO  10  PER  CENT.  EVERY  ^6  IN. 


Per 
cent. 

Toe, 
in. 

Per 
cent. 

Toe, 
in. 

Per 
cent. 

Toe, 
in. 

Per 
cent. 

Toe, 
in. 

Per 
cent. 

Toe, 
in. 

0.00 

2.00 

2Kfi 

4.00 

41K6 

6.00 

iy. 

8.00 

95^ 

0.05 

Me 

2.05 

/  1  D 

2^ 

4.05 

/ID 

4% 

6.05 

1    /4: 

7^6 

8.05 

47  '  O 

9% 

0.10 

H 

2.10 

2%6 

4.10 

4% 

6.10 

7% 

8.10 

m 

0.15 

Me 

2.15 

2% 

4.15 

5 

6.15 

7Ke 

8.15 

9% 

0.20 

H 

2.20 

2^6 

4.20 

5He 

6.20 

7^    , 

8.20 

9% 

0.25 

5/16 

2.25 

2% 

4.25 

5^ 

6.25 

7%6 

8.25 

9% 

0.30 

H 

2.30 

2^6 

4.30 

5Ke 

6.30 

7% 

8.30 

9^16 

0.35 

KG 

2.35 

2% 

4.35 

sy± 

6.35 

7% 

8.35 

10 

0.40 

H 

2.40 

2% 

4.40 

5^L6 

6.40 

7% 

8.40 

lOHe 

0.45 

X* 

2.45 

2% 

4.45 

5% 

6.45 

7^6 

8.45 

IOH 

0.50 

H 

2.50 

3 

4.50 

5Ke 

6.50 

7% 

8.50 

IOM^ 

0.55 

% 

2.55 

3He 

4.55 

5K 

6.55 

7^6 

8.55 

io>i 

0.60 

H 

2.60 

3M 

4.60 

5%6 

6.60 

7^6 

8.60 

IOK^ 

0.65 

% 

2.65 

3%6 

4.65 

5^ 

6.65 

8 

8.65 

10% 

0.70 

7/8 

2.70 

3^ 

4.70 

5^6 

6.70 

8He 

8.70 

lOKe 

0.75 

15/16 

2.75 

3^6 

4.75 

5^ 

6.75 

8^ 

8.75 

10^ 

0.80 

1 

2.80 

3% 

4.80 

5^6 

6.80 

8^6 

8.80 

10%6 

0.85 

iHe 

2.85 

3Ke 

4.85 

5% 

6.85 

8M 

8.85 

10% 

0.90 

IH 

2.90 

3H 

4.90 

5^6 

6.90 

8^6 

8.90 

10% 

0.95 

1^6 

2.95 

3Ke 

4.95 

5^6 

6.95 

8% 

8.95 

10% 

1.00 

IH 

3.00 

3« 

5.00 

6 

7.00 

8Ke 

9.00 

10^6 

GRADES 


57 


TOES  FOR  10-FT.  GRADE-BOARD  FROM  0  TO  10  PER  CENT.  EVERY 

IN. — (Continued) 


Per 
cent. 


Toe, 
in. 


Per 
cent. 


Toe, 
in. 


Per 
cent. 


Toe, 
in. 


Per 
cent. 


Toe, 
in. 


Per 
cent. 


Toe, 
in. 


1.05 
1.10 
1.15 
1.20 
1.25 

1.30 
1.35 
1.40 
1.45 
1.50 

1.55 
1.60 
1.65 
1.70 
1.75 

1.80 
1.85 
1.90 
1.95 
2.00 


w 

1% 
1% 


2% 
23-{6 

2^6 


3.05 
3.10 
3.15 
3.20 
3.25 

3.30 
3.35 
3.40 
3.45 
3.50 

3.55 
3.60 
3.65 
3.70 
3.75 

3.80 
3.85 
3.90 
3.95 
4.00 


3% 

3We 

3% 
3% 

3  We 

4 


4% 


5.05 
5.10 
5.15 
5.20 
5.25 

5.30 
5 . 35 
5.40 
5.45 
5.50 

5.55 
5.60 
5.65 
5.70 
5.75 

5.80 
5.85 
5.90 
5.95 
6.00 


6% 


6^6 

i 
6% 

6% 
6W6 


7^6 


7.05 
7.10 
7.15 
7.20 
7.25 

7.30 
7.35 
7.40 
7.45 
7.50 

7.55 
7.60 
7.65 
7.70 

7.75 

7.80 
7.85 
7.90 
7.95 
8.00 


8% 


8% 

m 

8  Wo 
9 


9^6 


9.05 
9.10 
9.15 
9.20 
9.25 

9.30 
9.35 
9.40 
9.45 
9.50 


9.60 
9.65 
9  70 
9.75 

9.80 
9.85 
9.90 
9.95 
10.00 


11 


12 


Another  convenient  way  is  to  make  the  level  board  100 
in.  long.  The  required  grade  per  cent,  expressed  in  feet 
is  then  equal  to  the  toe  required  in  inches;  the  length 
of  the  board  is  to  100  ft.  as  1  is  to  12,  or  as  1  ft.  is  to  an 
inch. 

For  Example. — On  a  grade  board  100  in.  long,  if  the 
grade  required  is  0.75  per  cent.,  the  toe  is  0.75  in.,  or  % 
in.  The  toe  ends  of  grade  boards  are  given  some  dis- 


58  MINE  TRACKS 

tinguishing  mark  to  avoid  confusion,  particularly  in  the 
flatter  grades. 

Wherever  possible,  gangways  and  headings  should  be 
driven  on  a  calculated  grade,  or  approach  as  closely  thereto 
as  is  practical.  This  should  be  done  if  only  for  the  sake 
of  haulage,  but  its  importance  in  the  event  of  future  de- 
velopments warranting  a  tunnel  to  connect  parallel  haulages, 
or  in  case  of  panel  mining,  is  inestimable.  A  system 
of  headings  or  gangways  graded  to  conform  with  one 
another  will  save  many  regrets  and  afford  many  economic 
possibilities. 

On  the  surface,  especially  where  the  adopted  grade  is  a 
factor  in  limiting  the  length  of  the  trip  of  cars,  the  inclina- 
tion on  curves  should  be  reduced;  so  that  the  grade  allowed 
on  the  curves  plus  the  resistance  due  to  curvature  will 
equal  the  grade  on  the  straight  track.  The  compensation 
or  allowance  for  curvature  is  usually  spoken  of  in  terms  of 
the  grade  proportional  to  the  degree  of  curve  as  discussed 
under  the  most  economic  radius  to  use  underground, 
page  34. 

For  Example. — If  the  prevailing  grade  for  the  road  is 
2.5  per  cent.,  then  on  a  100-ft.  radius,  or  57-deg.  curve, 
the  compensation  per  100  ft.  would  be  57  X  0.010  to 
57  X  0.025,  or  0.6  to  1.4  ft.  respectively,  depending  on 
the  particular  cars  used.  The  grade  on  the  curve  should 
be  1.9  to  1.1  ft.  per  100ft. 


CHAPTER  V 
GRAVITY  GRADES 

In  the  vicinity  of  shafts,  slopes,  planes,  etc.,  where  cars 
are  required  to  move  without  any  mechanical  aid,  it  is 
customary  to  depend  on  gravity  for  their  movement. 
It  is  impossible  to  adopt  a  gravity  grade  that  will  work 
equally  well  with  all  the  cars;  a  grade  upon  which  some 
cars  will  run  smoothly  will  permit  others  to  run  away  and 
will  not  be  sufficient  for  still. others.  Most  of  this  difficulty 
arises  from  the  oiling  of  the  cars,  the  flat  wheels  developed 
in  many  instances,  the  nonuniform  condition  of  mine  cars 
in  general,  and  the  temperature  and  the  weather. 

The  grade  in  the  immediate  vicinity  of  a  shaft  should 
be  sufficiently  steep  and  long  enough  to  permit  the  car  to 
gain  headway  quickly,  and  bump  off  the  car  delivered  to 
the  landing.  If  an  empty  car  is  to  drive  a  loaded  one  off 
the  cage,  greater  allowance  should  be  given  than  if  the  re- 
verse was  the  case. 

While  no  absolute  rule  can  be  given,  a  loaded  car  on 
a  grade  of  5  per  cent,  for  12  ft.  will  be  found  in  most  in- 
stances to  work  well  for  removing  empties  from  the  cage. 
When  the  cage  floor  is  inclined  in  favor  of  the  car  motion, 
a  2  per  cent,  to  2.5  per  cent,  grade  with  occasional  assistance 
from  the  cage  tender  has  given  satisfactory  results. 

With  the  empty  car  driving  off  the  loaded  one,  a  grade 
of  5  per  cent,  for  20  ft.  should  be  allowed;  or  with  occa- 
sional help  from  the  foot-  or  headman,  a  2.5  per  cent,  to 
3  per  cent,  grade. 

59 


60  MINE  TRACKS 

The  grade  of  the  track  leaving  the  cage  should  be  about 
2  per  cent,  to  2.5  per  cent,  in  order  to  assist  the  car  in 
leaving  the  shaft  quickly. 

It  is  customary  to  have  about  50  ft.  in  the  vicinity  of 
the  shaft,  plane  or  slope  landings  somewhat  steeper  than 
the  minimum  grade  required  for  the  car  to  start  unassisted, 
so  as  to  expedite  handling  the  cars.  The  remainder  of 
the  turnout  grade  should  run  about  1.5  per  cent,  to  1.7 
per  cent,  for  loaded  cars  and  from  1.6  per  cent,  to  1.9 
per  cent,  for  empty  cars,  on  the  straight  track.  A  stretch 
of  50  to  100  ft.  should  be  made  level  at  the  end  of  the 
turnout  to  retard  motion  and  prevent  the  cars  from  running 
upon  the  main  track. 

When  a  curve  occurs  on  a  gravity  grade,  the  compen- 
sation should  be  reversed;  that  is,  the  compensation  should 
be  added  to  the  regular  grade  used  for  the  tangents  in 
order  to  'allow  for  this  curve  resistance.  The  method  of 
computing  compensation  has  been  treated  previously. 

To  illustrate:     If  the  grade  for  straight  track  was  1.6 

per  cent,  on  a  100-ft.  radius,  or  57-deg.  curve, 


the  compensation  should  be  0.6  to  1.4  ft.  per  100  ft. 
The  grade  on  the  curve  would  thus  be  2.2  to  3  per  cent. 
Experience  will  determine  the  proper  allowance  to  use  for 
the  cars  employed. 

Cars  with  the  wheels  turning  loose  on  the  axles  will 
require  a  less  compensation  than  those  having  the  wheels 
keyed  to  the  axle.  The  curve  friction  which  the  compen- 
sation is  intended  to  equalize  is  due  to  the  pressure  of  the 
flanges  and  the  sliding,  both  lateral  and  longitudinal,  of  the 
wheels  on  the  rail  head. 

In  order  to  secure  an  easy  running  curve,  three  considera- 
tions are  necessary:  First,  to  elevate  the  outer  rail  to 


GRAVITY  GRADES  61 

allow  for  the  centrifugal  force  of  the  moving  cars;  second, 
to  widen  the  gage  of  the  track;  third,  to  ease  the  approaches 
to  the  curve. 

The  elevating  of  the  outer  rail  is  termed  the  super- 
elevation, and  its  amount  is  dependent  on  the  velocity 
at  which  the  cars  are  to  travel,  the  radius  of  the  curve, 
the  gage  of  the  track  and  the  weight  of  the  cars.  This 
superelevation  may  be  computed  from  the  formula: 

0  =  32.16# 
in  which 

0  =  Superelevation  required,  in  inches; 

V  =  Velocity  at  which  the  cars  are  to  travel,  in  feet 

per  second; 

g  =  Gage  of  the  track,  in  inches; 
R  =  Radius  of  the  curve,  in  feet. 

The  numeral  32.16  is  the  force  of  gravity.  By  the 
foregoing  formula  the  superelevation  for  a  velocity  of  6 
miles  per  hour  (the  maximum  velocity  allowed  by  law  in  a 
number  of  states  for  haulages  underground)  and  a  30-in. 
gage  track  should  be  as  follows : 

For  a    40  ft,  radius  curve 1%  in. 

For  a    50  ft.  radius  curve \%  in. 

For  a    60  ft.  radius  curve \y±  in. 

For  a    80  ft.  radius  curve l%    in. 

For  a  100  ft.  radius  curve M  in. 

For  a  150  ft.  radius  curve ^  in. 

For  a  200  ft.  radius  curve %  in. 

This  superelevation  varies  directly  as  the  gage,  so  that 
if  the  gage  was  40  in.,  the  superelevation  would  be  4%o> 
or  1^  times  as  great;  or  for  20  in.  2Mo>  or  %  as  great 
as  that  shown  in  the  table. 


62 


MINE  TRACKS 


The  elevation  varies,  as  will  be  noted  in  the  formula, 
as  the  square  of  the  velocity;  that  is,  if  the  velocity  is  12 
miles  per  hour,  instead  of  the  figure  for  6  miles  per  hour, 
for  which  the  table  was  computed,  the  superelevation 
would  be  (x%)2  or  4  times  as  great. 


FIG.   12. — Well-laid  narrow-gage  reverse  curve. 

For  Example. — If  the  gage  was  40  in.  and  the  velocity 
12  miles  per  hour,  the  superelevation  would  be  49lo  X 
(i%)2  =  1^  x  4,  or  5>i  times  that  shown  in  the  table. 
The  maximum  superelevation,  however,  should  not  exceed 
about  }/i  of  the  gage. 

In  applying  the  superelevation  the  best  practice  is  to 
start  same  a  distance  back  along  the  straight  track  ap- 


GRAVITY  GRADES  63 

preaching  the  curve  and  give  the  outer  rail  the  elevation 
gradually,  and  at  the  same  time  start  to  gently  curve 
the  track,  increasing  the  curvature  more  and  more  until 
when  the  curve  proper  is  reached  it  will  have  the  required 
maximum  curvature  and  full  superelevation. 

The  distance  used  to  reach  the  full  curvature  and  super- 
elevation will  depend  largely  on  the  amount  of  straight 
track  on  either  approach  to  the  curve;  where  possible,  it  is 
good  practice  to  elevate  1  in.  in  the  length  of  a  rail  and 
apply  the  curvature  in  the  same  distance.  To  gain  a  super- 
elevation of  2  in.,  would  mean  starting  two  rail  lengths  in 
advance  of  the  nominal  curve  and  achieving  the  elevation 
in  that  distance.  When  the  superelevation  and  curvature 
are  applied  skillfully,  there  should  be  no  jar  to  the  traffic 
when  the  curve  is  reached. 

The  maximum  speed  should  be  used  in  figuring  the  super- 
elevation. This  increase  in  height  of  the  outer  rail  when 
within  safe  bounds  tends  to  reduce  the  curve  resistance. 
When  the  cars  are  moved  by  rope  in  both  directions  over 
a  curve  the  inner  rail  should  be  elevated  instead  of  the 
outer,  as  the  motive  force  tends  to  draw  the  cars  toward 
the  inside  of  the  curve.  When  they  are  pulled  by  rope 
and  allowed  to  return  by  gravity,  pulling  the  rope  with 
them,  the  outer  rail  should  be  raised  but  not  to  the  full 
superelevation. 

INCREASING  GAGE  OF  TRACK  ON  CURVES 

The  cars  in  traveling  around  a  curve  do  not  move  con- 
centric to  the  axis  of  the  curve,  as  is  commonly  supposed, 
but  rather  in  a  series  of  short  tangents.  Fig.  13  shows 
the  normal  position  of  the  wheels  in  traveling  around  a 
curve. 

One  front  wheel  hugs  the  outer  rail  while  the  opposite 


64 


MINE  TRACKS 


back  wheel  tends  to  hold  to  the  inner  rail.  The  friction 
resulting  from  the  action  of  the  front  outer  wheel  of  course 
cannot  be  avoided;  the  flange  friction  of  the  hind  inner 
wheel,  however,  can  be  reduced  or  eliminated  by  widening 
the  gage  of  the  track.  The  position  that  the  rear  axle  and 
wheels  will  assume  when  free  to  move  is  radial  to  the  curve, 
so  that  when  the  gage  of  the  track  is  increased  sufficiently, 


*  ~  Gauge  of  Track  > 

<  Gauge  on  Curve  ^ 

Radius 

_J 

| 

^              1 
^              1 
I 

1         ! 

1 

FIG.  13. — Position  of  car  wheels  on  a  curve. 

no  friction  will  result  from  the  lateral  pressure  of  the  rear 
inner  wheel  flange  against  the  rail. 

Another  reason  why  the  track  gage  should  be  increased 
on  curves  is  that  if  any  advantage  is  realized  from  the 
coning  of  the  tread  on  the  car  wheels  in  consuming  the 
extra  length  of  the  outer  rail  (which  is  very  doubtful,  as 
the  position  assumed  by  the  rails  bears  no  relation  to  that 
required  by  the  coning),  it  can  be  better  effected  by  permit- 
ting the  lateral  action  necessary. 


GRAVITY  GRADES  65 

Also,  as  the  hind  lateral  pressure  is  reduced,  there  is  less 
force  tending  to  narrow  the  wheel  gage  and  produce  an 
excess  play  on  the  axles,  which  trouble  is  quite  common 
where  the  wheels  revolve  on  the  axle. 

The  distance  which  the  gage  of  the  rails  can  be  increased 
is  small,  depending  on  the  widths  of  the  wheel  treads,  the 
condition  of  the  wheel  gage  and  the  radius  of  the  curve; 
one  in.  is  about  the  maximum  with  ordinary  rolling  stock. 

The  distance  which  the  rear  outer  wheel  stands  from 
the  outer  rail  on  a  curve,  is  the  theoretic  distance  that  the 
gage  should  be  widened,  and  is  equal  to  the  versed  sine  of 
the  chord  subtended  by  twice  the  length  of  wheelbase. 

Expressing  this  relation  as  a  formula: 

Let 

/  =  Theoretic  distance  in  feet  that  the  gage  should 
be  increased  beyond  the  gage  of  the  car  wheels  ; 
L  =  Length  of  wheelbase  of  the  cars,  in  feet; 
R  =  Radius  of  curve,  in  feet; 
A  =  Angle  subtended  by  the  wheelbase. 

sin  A  =  p 

K 

Then 

I  =  R  vers  sin  A. 

For  Example.  —  If  the  car  has  a  5-ft.  wheelbase,  the 
theoretic  distance  the  gage  should  be  increased  on  a  1-deg. 
curve  is: 

sin  A  =  ^^-     A  =  0  degrees  3  minutes. 


7  =  5730  vers  sin  A  =  0.0022  ft.; 
in   which  5730'  =  radius  of  a   1-deg.   curve, 
and    1  —  cos    A  =  vers  sin  A  . 


66 


MINE  TRACKS 


This  increase  in  gage  should  be  applied  gradually,  as 
explained  under  superelevation.  The  theoretic  distance 
required  in  excess  of  the  wheel  gage  is  as  follows: 


Radius,  ft. 

Wheelbase 
1Yt  ft. 

Wheelbase 
3  ft. 

Wheelbase 

Wheelbase 
4  ft. 

40 

H  in. 

1%  in. 

1%  in. 

236  in. 

50 

%  in. 

\M  in. 

!}-£  in.            2      in. 

60 

%  in. 

%  in. 

1M  in. 

1%  in. 

75 

1A  in. 

%  in. 

1      in. 

1M  in. 

100 

%  in. 

%6  in. 

Y±  in. 

1       in. 

150 

/i  in. 

%  in. 

/^  in. 

%  in. 

200 

2i6  in. 

y\  6  in. 

%  in. 

^  in. 

The  foregoing  distances  apply  to  the  wheel  gage,  not 
the  track  gage,  and  as  mentioned  before  the  increase 
above  the  track  gage  will  hardly  be  permitted  to  exceed 
1  in.,  unless  the  treads  are  unusually  wide. 

Taking  the  case  of  a  50-ft.  radius  curve  with  a  3j^-ft. 
wheelbase,  the  track  gage  being  J^  in.  greater  than  the 
gage  of  the  wheels,,  the  theoretic  increase  is  \Y^  in.,  which, 
as  there  is  J£  in.  allowance  between  the  track  gage  and 
the  wheel  gage,  and  the  treads  of  the  wheels  permit  another 
inch,  the  full  increase  can  be  given. . 

With  a  4-ft.  wheelbase  and  J^-in.  play  between  the 
gages  on  a  40-ft.  radius  curve,  if  1  in.  above  track  gage  is 
allowed,  there  will  be  %-in.  deficiency.  This  deficiency 
will  have  a  resisting  effect  equal  to  the  force  required  to 
move  the  weight  on  the  hind  wheels  %  m-  over  the  length 
of  the  curve. 

GUARD  RAILS 

When  guard  rails  are  necessary  on  curves  they  should 
be  placed  parallel  to  and  at  such  a  distance  from  the  inner 


GRAVITY  GRADES  67 

rail  that  they  will  restrain  the  flange  of  the  front  wheel 
from  running  over  the  head  of  the  outer  rail. 

Where  the  wheels  are  not  true  to  gage,  as  is  often  the 
case  with  loose  wheels,  the  guards  in  this  position  are  not 
very  effective.  Placing  the  guard  at  a  distance  equal  to 
the  tread  of  the  wheels  on  the  outer  side  of  the  outer  rail 
and  about  1  in.  higher  is  often  resorted  to. 

With  rope  haulage,  the  guard  should  be  placed  at  a 
distance  equal  to  the  width  of  the  tread  outside  the  inner 
rail.  At  the  bottoms  of  slopes  and  similar  places,  since 
the  force  is  contrary  in  hoisting  and  lowering,  the  guard 
should  be  placed  outside  of  both  rails. 

On  planes  and  slopes  it  is  good  practice  to  have  guards 
even  though  the  track  is  straight.  Such  guards  are  usually 
made  of  wood  and  covered  with  flat  or  angle  iron,  and  are 
made  as  high  as  the  axle  and  journal  box  will  allow.  The 
type  of  journal  and  oil-box  used  on  the  cars,  together  with 
local  conditions,  will  determine  whether  the  guards  should 
be  placed  inside  or  outside  of  the  rails. 

If  the  guards,  when  placed  outside  the  inner  rail  of  the 
curve,  are  made  of  "T"  rail,  and  are  spiked  to  ties  distinct 
from  those  supporting  the  main  rails,  they  can  be  more 
readily  brought  back  to  the  tread  distance  as  they  wear  or 
are  forced  out  of  alignment.  If  the  same  or  a  lesser  weight 
rail  is  used  for  the  guard  rail,  than  for  the  main  rails,  the 
requisite  elevation  above  the  main  rails  is  usually  obtained 
by  notching  the  guard  rail  ties  directly  under  the  one  main 
rail. 


CHAPTER  VI 
FROGS  AND  SWITCHES 

The  standardization  of  turnout  equipment  furnishes  a 
fertile  field  for  improvement;  both  time  and  equipment 
can  be  economized  and  at  the  same  time  better  results 
obtained. 


FIG.   14. — Typical  plate  frog  of  uniform  length  for  varying  weights  of  rail. 

In  the  preparation  of  standards,  every  effort  should  be 
made  to  achieve  simplicity — the  adoption  of  three  or  four 
different  numbered  frogs  with  possibly  two  switches  of 
different  lengths  that  can  be  installed  to  suit  most  conditions, 
if  a  little  forethought  is  used  in  laying  out  the  work,  will 
be  found  ample. 

The  use  of  a  frog  of  a  certain  number  for  chamber  work, 
another  for  general  cases  other  than  the  chambers,  and  a 

68 


FROGS  AND  SWITCHES  69 

third  for  locations  subject  to  heavy  traffic  and  high  velocity 
will  be  sufficient  except  for  special  cases. 

Plate  frogs  should  be  designed  so  they  can  be  made, 
should  the  necessity  arise,  at  the  colliery  blacksmith  shop, 
although  ordinarily  it  will  be  found  advisable  to  purchase 
such  frogs  from  a  manufacturer  who  specializes  in  this 
kind  of  equipment.  The  reasons  for  this  latter  choice  are, 
of  course,  obvious. 

If  the  mine  employs  various  weights  of  rail,  by  designing 
a  certain  number  of  frogs  the  same  length  for  the  different 
weights,  the  one  turnout  standard  will  apply.  This  will 
also  permit  in  an  emergency  the  replacing  or  temporary 
installation  of  any  frog  of  a  certain  number  with  rail  of 
different  weights.  With  this  idea  in  view,  a  No.  4  frog 
would  be  the  same  length,  whether  made  of  30-,  40-  or 
60-lb.  rail. 

Fig.  14  shows  a  typical  frog  design  for  a  No.  3,  4  or  6 
frog  to  be  used  with  any  weight  rail  up  to  and  including 
60  Ib.  per  yard.  The  length  of  the  frog  must  be  suffi- 
cient to  permit  the  easy  application  of  the  angle  bars. 


FIG.  15. 

While  frogs  are  sometimes  lettered  or  numbered  ar- 
bitrarily, the  generally  accepted  practice  is  to  designate 
the  frog  by  the  number  found  by  dividing  the  length  by 
the  spread;  that  is,  the  frog  number  is  the  ratio  of  the 
length  to  the  spread.  Thus,  referring  to  Fig.  15: 


70  MINE  TRACKS 

Let 

L  =  Double  or  entire  length  of  the  frog; 

A  =  Spread  between  gage  side  of  rails  at  one  end  of  the 

frog; 
B  =  Spread  between  gage  side  of  rails  at  the  other  end  of 

the  frog. 

Then  the  frog  number  equals  -i — '—^,  or  the  frog  number 

A.    ~f~   JD 

L' 

equals  -r' 

If  L  is  measured  in  inches,  then  A  and  B  should  be 
in  inches;  and  similarly,  if  L  is  in  feet,  A  and  B  should 
be  in  feet. 

The  use  of  the  cast  frog  is  not  to  be  recommended  with 
locomotive  haulage,  and  even  with  mule  haulage  and  light 
rail  it  should  be  restricted  to  chamber  or  room  work.  While 
the  initial  cost  of  the  cast  frog  is  less  than  for  the  built-up 
frog,  it  will  not  wear  as  well;  the  point  breaks  off  or  wears 
down  in  a  short  time;  it  does  not  permit  an  efficient  con- 
nection with  the  rails;  it  wears  down  quickly  and  con- 
tributes to  many  derailments. 

Many  companies  require  the  face  of  such  frogs  to  be 
chilled  in  order  to  increase  the  wearing  qualities.  Fig. 
16  shows  a  shrouded  cast  frog;  the  shrouded  type  being 
found  much  superior  to  the  ordinary  casting  in  the  pre- 
vention of  derailments.  The  shroud  precludes  the  possi- 
bility of  the  flange  hitting  the  frog  point  or  taking  the 
wrong  flange  channel  when  passing  from  the  throat  of  the 
frog.  It  will  be  noted  that  the  shroud  is  cast  about  1  in. 
higher  than  the  frog,  and  at  such  a  distance  from  the  gage 
lines  that  the  shroud  engages  the  outside  of  the  wheel 
tread  a  short  distance  before  the  point  is  reached. 

The  use  of  the  usual  guard  rail  on  the  inner  side  of 


FROGS  AND  SWITCHES 


71 


* 


SECTION  ff-A 


FIG.   16. — Plan  of  shrouded  cast  frog. 


FIG.   17. — Tee  rail  shroud  with  spring. 


72 


MINE  TRACKS 


the  opposite  rail  is  not  so  positive  in  its  action  as  the 
shroud  even  for  wheels  tight  on  the  axles,  and  with  the 
play  common  to  wheels  loose  on  the  axles,  the  guard  rail 
is  extremely  unreliable.  Moreover,  the  shroud  is  cheaper 
and  easier  to  install  than  the  guards. 

A  similar  shroud  has  been  found  satisfactory  with  the 
plate  or  built-up  frog,  particularly  with  the  long  throats 
of  those  of  a  larger  number. 

If  the  tread  of  the  locomotive  is  the  same  as  that  of  the 
cars,  the  shroud  is  riveted  to  the  plate;  otherwise,  the 


SECTION  A~A 

FIG.  17A. — Plan  of  spring-rail  shroud  frog. 

shroud  is  held  in  the  position  required  for  the  cars  by  a 
spring,  which  the  locomotive  pushes  back  when  passing. 
It  will  be  noted  that  one  spring  will  serve  for  either  a 
single  or  double  shroud  (see  Fig.  17). 

Fig.  17 A  is  a  plan  of  a  shroud  built  of  ordinary  tee  rail, 
the  elasticity  of  the  rail  constituting  the  shroud  maintaining 
it  in  position. 

In  designing  either  plate  or  cast  frogs,  the  flange  channels 
should  be  made  as  narrow  as  the  flanges  of  the  wheels 


FROGS  AND  SWITCHES 


73 


will  permit.  There  are  two  objections  to  a  wide  flangeway: 
First,  the  diameter  of  the  wheels  of  mine  cars  is  compara- 
tively small,  so  that  instead  of  spanning  the  gap  between 
the  point  and  the  wing  they  drop  partly  into  it,  jarring  the 
cars  and  wearing  out  the  frog;  second,  the  wider  the  flange- 
way  the  longer  will  be  the  ''throat"  of  the  frog — that  is, 
the  distance  between  the  point  and  the  "wing" — and  the 
wheels  in  traveling  over  the  throat,  especially  of  the  frogs  of 


Eccenfrlc 


Lever 


^Eccentric 


FIG.  18. 

large  number,  are  more  liable  to  depart  from  their  proper 
course  and  derail  the  car  by  striking  the  frog  point  or  by 
taking  the  wrong  flangeway.  As  stated  before,  the  guard 
rail  placed  near  the  opposite  rail  cannot  be  depended  upon 
when  the  cars  have  loose  wheels.  The  short  length  of  mine 
frogs  does  not  adapt  them  for  having  one  wing  on  a  spring, 
as  may  be  the  case  on  standard-gage  tracks;  and  further- 
more, wheels  loose  on  the  axle  would  not  operate  a  spring 
frog. 


74  MINE  TRACKS 

Fig.  18  shows  a  form  of  frog  built  to  avoid  the  gap  in  the 
usual  type.  It  is  generally  connected  with  the  switch 
lever,  so  that  whichever  way  the  switch  is  set  the  frog  will 
be  in  proper  relation.  The  tongue  is  held  by  a  pin  which 
allows  it  to  swing  to  fit  either  of  the  rails.  About  3  in. 
are  left  between  the  ends  of  the  rails — the  tongue  is  made 
sufficiently  long  to  reach  from  the  frog  point  and  make  a 
close  joint  with  the  ends  of  the  rails. 

This  arrangement  has  been  found  to  work  well  in  pre- 
venting derailments  where  cars  are  pushed.  On  switches 
where  the  cars  run  always  in  one  direction  (E  to  F  in  the 
figure),  the  cars  themselves  set  the  frog  point.  This 
movable  frog  point  will  usually  outlast  the  ordinary  type. 

In  frogs  for  crossings  over  other  tracks,  the  flange- 
ways  should  be  made  as  narrow  as  the  mine  cars  will  permit. 
If  the  mine  cars  are  equipped  with  wheels  which  run  loose 
on  the  axle,  the  angle  of  the  crossing,  if  possible,  should  not 
be  less  than  10  deg.;  otherwise,  derailments  may  occur 
when  passing  through  the  frogs  toward  the  point. 

SPLIT  SWITCHES  AND  LATCHES 

The  length  of  the  switch  point  should  be  in  conformity 
with  the  radius  of  the  turnout  curve  and  the  speed  and 
character  of  the  traffic. 

The  tapered  end  of  the  switch  is  known  as  the  point; 
the  blunt  end,  the  heel.  The  switch  made  of  tee  rail 
is  termed  a  split  switch;  that  made  of  a  bar  of  iron  which 
turns  on  a  pin  near  its  heel  is  known  as  a  latch.  Switch 
points  are  designated  right  and  left  hand  and  are  not  inter- 
changeable, the  right  and  left  hand  being  determined  by 
standing  at  the  switch  point  and  facing  toward  the  frog. 
When  ordering  a  single  switch  point,  its  position,  right  or 


FROGS  AND  SWITCHES  75 

left,  must  be  given.  No  distinction  is  necessary  with 
latches  as  they  can  be  reversed  and  used  for  either  side. 

Split  switches  for  mine  work  should  be  straight,  not 
curved,  so  that  any  pair  of  mated  switch  points  can  be 
used  on  a  right-  or  left-hand  turnout.  When  light  rail 
switch  points  are  curved,  they  frequently  break  a  short 
distance  from  the  point. 

The  split  switch  is  usually  longer  than  the  latch  and  is 
operated  by  a  lever.  It  thereby  makes  a  more  efficient 
bearing  against  the  rail  and  affords  a  smoother  haulage  than 
does  the  latch.  It  is  known  as  a  rigid  split  switch  when 
used  without  a  spring,  and  as  a  spring  switch  when  a 
spring  is  employed.  The  spring  makes  the  switch  auto- 
matic and  is  profitably  used  at  turnouts  when  the  traffic 
is  in  one  direction.  .  For  ordinary  use  underground,  the 
spring,  if  not  properly  cared  for,  clogs  with  mud  and  is 
no  better  than  the  rigid  switch.  The  bolts  attaching 
the  rods  connecting  the  switch  points  should  be  sufficiently 
low  so  that  when  the  treads  of  the  motor  wheels  are  well 
worn  the  flanges  will  not  cut  the  bolts.  It  is  often  advisable 
to  attach  the  connecting-rods  to  the  flange  of  the  switch 
points  rather  than  to  the  web. 

The  latches  in  general  use  on  mine  tracks  run  from 
2  to  5  ft.  in  length  and  the  split  switches  from  5  to  10  ft. 
Due  to  its  easy  and  cheap  installation,  the  latch  is  much  used 
for  mule  haulage  and  chamber  work. 

The  use  of  the  stub  switch  has  been  limited  around 
mines.  It  is  assumed  that  it  is  a  simple  curve  from  the 
point  of  the  stub  to  the  point  of  frog;  the  lead  being  found 
by  multiplying  twice  the  gage  by  the  number  of  the  frog 
and  the  radius  by  multiplying  twice  the  gage  by  the  frog 
number  squared.  For  example:  If  the  frog  is  a  No.  3 
and  the  gage  3^  ft.,  the  lead  is  21  ft.  and  the  radius  63  ft. 


76 


MINE  TRACKS 


The  following  table  gives  the  angles  corresponding  to 
the  various  length  switches  and  frogs: 


Frog  no. 

Frog  angle 

Split  switch 
lengths,  ft. 

Switch  angle  for  5-in. 
throw;    switch,     J^    in. 
at  point 

Deg. 

Min. 

Deg. 

Min. 

M 

33 

12 

5 

4 

32 

2 

28 

56 

5% 

4 

08 

2% 

23 

04 

6 

3         |        47 

3 

19 

12 

6;Hj 

3 

27 

3H 

4 

16 
14 

25 
22 

7 

3 
3 

15 
01 

±Y2 

12 

46 

8X 

2 

50 

5 

11 

30 

9 

2 

31 

5/^ 

10 

26 

10 

2 

16 

6 

9 

34 

7 

8 

10 

.  . 

8 

7 

09 

FIG.  19. — Dimensions  of  plate  frog  of  25-  to  60-lb.  rail. 


FROGS  AND  SWITCHES 


77 


The  accompanying  tables  give  dimensions  for  frogs  from 
No.  3  to  5H  for  rail  from  25-  to  60-lb.  weight  per  yard  : 


STANDARD  RIVETED  PLATE  FROGS  FOR  25-LB.  RAIL 


6 
c 

2 

Frog  angle 

jl 

|j 

"8 

1. 

•2.£ 

General  Dimensions 

IS 

"s! 

s 

A 

B 

c 

D 

E 

F 

G 

H 

J 

Deg. 

Min. 

In. 

In. 

Ft. 

In. 

In. 

In. 

In. 

In. 

In, 

In. 

In. 

Ft 

In. 

In. 

3 
4 
5 

19 
16 
14 
12 
11 
10 

12 
25 
22 
46 
30 
26 

IK 

IK 

IK 

|| 

0 
0 
2 
2 
2 
2 

21 
24 
3 
3 
6 
9 

15 
15 

18 
18 
18 
21 

5 

4%2 
4>£ 
4 
3X 

3^6 

7 
6% 

6 
6 
6 

K 
i 

5 

5^ 

6% 

9 
9 
9 
9 
9 
9 

16 
16 
16 
16 
16 
16 

0 
0 
2 
2 
3 
3 

24 
24 
6 
6 
0 
6 

|\w  \w  \w  \ec  \»  \t« 
od\  o*\  otfx  OK  otfs  o!s 

STANDARD  RIVETED  PLATE  FROGS  FOR  30-LB.  RAIL 


•3 

11 

0 

Li 

General  Dimensions 

| 

§ 

§ 

•°  n 

"S    03 

•*» 

% 

* 

§"* 

03    > 

1 

CQ^ 

A 

B 

C 

D 

E 

F 

G 

H 

J 

04 

Deg.    Min. 

In.    |"In. 

Ft. 

In. 

In. 

In. 

In. 

In. 

In. 

In. 

In. 

Ft. 

In. 

In. 

3 

19 

12 

m 

K 

2 

3 

18 

6 

9 

K 

4H 

9 

16 

0 

24 

H 

3>3 

16 

25 

IK 

K 

2 

6 

21 

6 

8%  6 

% 

*K 

9 

16 

0 

24 

X 

4 

14 

22 

IK 

K 

2 

9 

21 

5K 

&K 

1 

5^£ 

9 

16 

2 

6 

X 

4>£ 

12 

46 

IK 

3 

0 

24 

5H 

8 

i>| 

6>^ 

9 

16 

2 

6 

X 

5 

11 

30 

IK 

K 

3 

3 

24 

4*  Me 

7»Me 

IK 

6K 

9 

16 

3 

0 

X 

5H 

10 

26 

IK 

H 

3 

6 

24 

4« 

7% 

IX 

7>^ 

9 

16 

3 

6 

X 

78 


MINE  TRACKS 


STANDARD  RIVETED  PLATE  FROGS  FOR  40-LB.  RAIL 


a 

% 

•1 

11 

"o 

General  Dimensions 

o 

0 

^  *o 

0> 

1 

55 

2 

g.g 

11 

0> 

£ 

JM 

Q'C 

A 

B 

C 

D 

E 

F 

G 

B. 

J 

s 

Deg. 

Min. 

In. 

In. 

Ft. 

In. 

Ft. 

In. 

In. 

In.    |ln. 

In. 

In. 

In. 

Ft. 

In. 

In. 

3 

19 

12 

IK 

H 

2 

9 

0 

2! 

7 

11 

K 

4% 

9 

16 

0 

24 

H 

3>£ 

16 

25 

IK 

>S 

3 

0 

0 

24 

62^J2 

10K 

K 

5K 

9 

16 

0 

24 

K 

4 

14 

22 

IK 

M 

3 

3 

0 

24 

6 

9K 

1 

6>3 

9 

16 

2 

6 

H 

4H 

12 

46 

IK 

M 

3 

6 

2 

3 

6 

9^6 

IJ-i 

7K 

9 

16 

2 

6 

>6 

5 

11 

30 

IK 

H 

3 

9 

2 

3 

5% 

9 

IK 

8J-6 

9 

16 

3 

0 

H 

5M 

10 

26 

IK 

H 

4 

0 

2 

3 

4^6 

8K 

IK 

9 

9 

16 

3 

6 

M 

STANDARD  RIVETED  PLATE  FROGS  FOR  45-LB.  RAIL 


e 

| 

0 

ii 

0 

General  Dimensions 

| 

o 

S5 

§ 

«•§ 

1 

2 

I 

9 

£ 

0  rt 

M 

02  -^ 

ll 

1?; 

A 

B 

C 

D 

E 

F 

G|H 

J 

Deg. 

Min. 

In. 

In. 

Ft. 

In. 

Ft. 

In. 

In. 

In. 

In. 

In. 

In. 

In. 

Ft. 

In. 

In. 

3 

19 

12 

IK 

H 

2 

9 

0 

24 

8 

11 

K 

5K 

10 

18 

2 

6 

}* 

3H 

16 

25 

IK 

% 

3 

0 

0 

24 

6K 

10K 

K 

6>^ 

10 

18 

2 

6 

M 

4 

14 

22 

IK 

% 

3 

6 

0 

21 

6 

iOH 

1 

7 

10 

18 

3 

0 

M 

4M 

12 

46 

IK 

% 

3 

9 

2 

3 

6 

10 

1J-^ 

7K 

10 

18 

3 

6 

H 

5 

11 

30 

IK 

% 

4 

0 

2 

3 

5Jie 

9%  6  'lK 

8K 

10 

18 

3 

6 

M 

5>^ 

10 

26 

IK 

y* 

4 

3 

2 

3 

4i<K6 

9K     IK 

9« 

10 

18 

4 

0 

H 

AND  SWITCHES 


79 


STANDARD  RIVETED  PLATE  FROGS  FOR  50-LB.  RAIL 


A 

• 

«),-« 

J! 

11 

"o 

General  'Dimensions 

"3 

1 

03 

2* 

a; 
V  m 

3 

• 

1 

H 

0 

11 

1! 

Q'c 

1 

OH 

A 

B 

C         D 

E 

F 

G 

H 

J 

Deg. 

Min. 

In. 

In. 

Ft. 

In. 

Ft. 

In. 

In.    |   In. 

In. 

In.  |ln. 

In. 

Ft. 

In. 

In. 

3 

19 

12 

IK    % 

3 

0 

0 

24  'g          12 

K 

5% 

10 

20 

2 

6 

K 

3H 

16 

25 

1K|  H 

3 

3 

0 

24  |6K     UK 

H 

6M 

10 

20 

2 

6 

K 

4 

14 

22 

IK   % 

3 

6 

0 

24    6          IOK 

1 

7K 

10 

20 

3 

0 

K 

*K 

12 

46 

IK    % 

3 

9 

2 

3 

6          10 

IK 

8% 

10 

20 

3 

6 

K 

5 

11 

30 

IK    % 

4 

0 

2 

3 

5Ke     9Ke 

IK 

9% 

10 

20 

3 

6 

K 

5H 

10 

26 

IK    % 

4 

3 

2 

3 

4>Me!  9K 

1% 

IOK 

10 

20 

4 

0 

K 

STANDARD  RIVETED  PLATE  FROGS  FOR  60-LB.  RAIL 


fa 

General  Dimensions 

1 

g 

%  *" 

0 

•% 

0 

r\  *O 

Q 

_e 

£ 

§ 

V  a° 

4J    OQ 

" 

M 

5? 

«"^2 

•3 

£ 

1 

JM 

g'C 

A 

B 

C 

D 

E 

F 

G 

H 

'  J 

s 

Deg. 

Min.  |  In. 

In. 

Ft. 

In. 

Ft. 

In. 

In. 

In. 

In. 

In. 

In. 

In. 

Ft. 

In. 

In. 

3             19 

12 

2 

% 

3 

0 

0 

24 

8 

12 

K 

6% 

10 

20 

2 

6 

H 

3M 

16 

25 

2      % 

3 

G 

0 

24 

12 

% 

7% 

10 

20 

2 

6 

H 

4  , 

14 

22 

2     % 

3 

9 

0 

24 

6 

11^6 

1 

8>£ 

10 

20 

3 

0 

H 

4>6 

12 

46 

2 

% 

4 

0 

2 

3 

6 

10% 

IK 

9K 

10 

20 

3 

6 

% 

5 

11 

30 

2 

4 

3 

2 

3 

5Ke 

10% 

IK 

10% 

10 

20 

3 

6 

% 

&H 

10 

26 

2      % 

4 

9 

2 

6 

5Jf« 

1% 

11%    10 

20 

4 

0 

% 

NOTE. — Rivets  to  he  countersunk  on  bottom  side  of  bottom  plate;  frogs  to  be 
drilled  for  standard  splice  bars. 


80  MINE  TRACKS 

The  assumption  that  a  turnout  is  a  simple  curve  from 
the  point  of  switch  to  the  point  of  frog  is  no  longer  tenable. 
By  the  simple  curve  theory,  the  lead  was  found  by  multi- 
plying twice  the  gage  by  the  number  of  the  frog;  the  radius 
of  the  curve  by  multiplying  twice  the  gage  by  the  square 
of  the  number.  The  above,  of  course,  ignores  the  fact  that 
the  frog  is  straight  and  not  curved,  and  the  switch  points 
are,  especially  for  mine  work,  also  straight. 

In  standardizing  the  switch  design,  the  frog  numbers  to 
be  used  and  the  length  of  switch  point  to  accompany  each 
frog  should  first  be  determined.  The  design  of  each  frog 
and  switch  proposed  should  be  gone  into  thoroughly  and 
the  types  adopted  rigidly  adhered  to.  Local  conditions 
will  determine  the  frog  angles  and  switch  points  most 
suitable. 

Companies  purchasing  their  equipment  from  manu- 
facturers will  find  it  advisable  to  state  the  frogs  and  switches 
they  propose  to  use  and  have  the  builders  of  such  equip- 
ment furnish  designs  of  the  entire  turnout.  For  the  con- 
venience of  the  companies  who  make  their  own  frogs  and 
switches,  the  following  formulae  are  given.  Referring  to 
Fig.  20: 

Let 

0  =  Angle  of  switch  points; 

F  =  Angle  of  frog; 

G  =  Gage  of  track; 

B  =  Length  of  wing  rail; 

C  =  Chord  of  connecting  rail  arc; 

S  =  Length  of  switch; 

L  =  Length  of  lead; 

R  =  Radius  of  center  line  of  turnout  curve; 

H  =  Connecting  rail  length; 

D  =  Distance  from  theoretical  to  actual  frog  point. 


FROGS  AND  SWITCHES 


81 


82  MINE  TRACKS 

Then 

G  —  B  sin  F  —  S  sin 


Or 


G-BsinF-H 

cos*-  cos  F 


L  =  (R+  y^G]  (sin  F-  0)  +  B  cos  F  +  S+  DC. 

Table  I  has  been  worked   from  the  foregoing  formulae 

—  the  actual  shape  and  size  of  the  frog  and  switch  are  used 

—  a  simple  curve  connecting  the  heel  of  the  switch  with  the 
end  of  the  frog. 

The  dimensions  in  the  table,  of  course,  are  only  ap- 
plicable to  turnouts  having  the  same  switch  lengths  and 
the  same  wing  rails  used  in  the  table.  As  stated  before, 
to  a  certain  extent  the  frogs  made  from  different  weights 
of  rail  can  be  made  the  same  dimensions,  so  that  one  turn- 
out design  for  any  frog  of  a  given  number  will  be  sufficient. 
Similar  tables  should  be  furnished  the  trackman  for  the 
various  turnouts  to  be  installed. 

Some  trackmen,  instead  of  using  the  actual  length  of  the 
frog  from  the  point  to  the  end  of  the  wing  rail  (B  in  the 
formula),  prefer  to  have  a  tangent  from  the  point  of  the 
frog  for  a  distance  not  less  than  a  few  inches  greater  than 
the  wheelbase  of  the  mine  cars  used.  This  is  done  in  order 
that  both  wheels  of  the  car  may  be  traveling  in  a  straight 
line  before  the  point  is  reached;  and  if  this  is  desired,  B 
in  the  formula  should  be  made  equal  to  this  distance. 
Naturally,  where  the  length  of  the  wing  rail  is  greater  than 
the  wheel-base,  the  length  of  the  wing  rail  should  be  used. 

To  determine  the  angle  of  the  switch  points  or  latches, 
the  heel  distance  which  should  be  4  to  5  in.,  is  divided  by 


FROGS  AND  SWITCHES 


83 


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84 


TRACKS 


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FROGS  AND  SWITCHES 


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86 


MINE  TRACKS 


FROGS  AND  SWITCHES  87 

the  length  of  the  points;  the  result  is  the  sine  of  the  switch 
angle.  The  less  the  angle  the  less  the  shock  to  the  motion 
of  the  cars,  and  consequently  the  greater  speed  and  safety 
with  which  the  rolling  stock  will  travel  over  the  switch. 

There  are  locations,  however,  where  the  amount  of  room 
is  limited,  and  shorter  frogs  or  switch  points,  or  both,  must 
be  resorted  to;  and  the  extreme  to  which  this  can  be  carried 
will  be  governed  by  the  radius  R  of  the  lead  curve,  com- 
bined with  practical  experience. 

When  the  frog  and  switch  standardization  has  been 
decided  upon,  and  the  designs  for  the  complete  turnouts 
have  been  made,  the  various  parts  of  the  turnout,  including 
the  frogs,  switches,  points,  the  middle  rail  curved  to  the 
proper  radius  and  drilled,  and  all  the  other  parts,  should 
be  carried  in  stock,  so  that  when  it  is  desired  to  install  a 
turnout,  all  that  will  be  necessary  is  to  specify  the  frog 
number  desired  and  the  entire  equipment  can  be  delivered 
to  the  site  desired  and  will  require  a  minimum  of  labor 
to  install.  The  ties  for  the  turnout  should  be  in  graded 
lengths  to  carry  both  the  main  and  turnout  curve  as  far 
as  the  end  of  the  frog.  Such  ties  would  be  delivered  with 
the  rest  of  the  turnout  equipment. 

It  is  obvious  that  by  having  this  equipment  standard, 
and  thereby  interchangeable,  great  economy  can  be  achieved 
in  both  the  original  installation  and  renewals. 

TURNOUTS  OFF  CURVES 

For  all  practical  purposes,  the  lead  of  a  turnout  off  a 
curve,  whether  from  the  inside  or  outside  of  the  curve,  is 
the  same  as  the  lead  off  a  straight  track.  The  radius  of  the 
curve  connecting  the  frog  and  switch  points.,  however, 
will  increase  or  decrease,  depending  on  whether  the  turnout 
is  to  the  outside  or  the  inside  of  the  main  curve. 

7 


88 


MINE  TRACKS 


TABLE  2. — RADII,  DEGREES  OF  CURVE  AND  ORDINATES  BASED  ON 
A  10-FT.  CHORD 


Radi- 
us, ft. 

Degree  of 
curve 

Middle 
ordinate  of 
10-ft.  chord 

Radius, 

ft. 

Degree  of 
curve 

Middle 
ordinate  of 
10-ft.  chord 

Deg. 

Min. 

Ft. 

In. 

Deg. 

Min. 

Ft. 

In. 

15 

39 

00 

3 

9K 

18 

32 

20 

3 

0% 

20 

29 

00 

2 

22 

26 

20 

2 

4% 

24 

24 

00 

2 

2*6 

26 

22 

10 

2 

0 

28 

20 

30 

1 

IW/i 

30 

19 

12 

&H 

32 

17 

58 

1 

71A 

34 

16 

54 

6 

36 

15 

58 

1 

5 

38 

15 

08 

3 

40 

14 

22 

1 

3 

42 

13 

40 

2K 

44 

13 

2 

1 

1% 

46 

12 

28 

1*6 

48 

11 

58 

1 

1^ 

50 

11 

28 

1 

0 

52 

11 

2 

0 

11** 

54 

10 

38 

0 

11*6 

56 

10 

14 

0 

10*6 

58 

9 

53 

0 

io*i 

60 

9 

34 

0 

10 

62 

9 

15 

0 

9% 

64 

8 

58 

0 

9% 

66 

8 

41 

0 

9V£ 

68 

8 

26 

0 

8% 

70 

8 

12 

0 

8% 

72 

7 

58 

0 

8% 

74 

7 

45 

0 

&i 

76 

7 

33 

0 

7% 

78 

7 

21 

0 

7% 

80 

7 

10 

0 

7% 

85 

6 

45 

0 

7 

90 

6 

22 

0 

6% 

92 

6 

14 

0 

6*£ 

95 

6 

2 

0 

6K 

100 

5 

44 

0 

6 

105 

5 

28 

0 

5% 

110 

5 

13 

0 

5*A 

115 

4 

59 

0 

5j| 

120 

4 

47 

0 

5 

130 

4 

25 

0 

4% 

140 

4 

6 

0 

4*4 

150 

3 

49 

0 

4 

160 

3 

35 

0 

3% 

170 

3 

22 

0 

3/£ 

180 

3 

11 

0 

3JMt 

190 

3 

1 

0 

m 

200           2 

52 

0 

3 

Degree  of  curve  =  radius (approximate) 

Ordinates  midway  between  middle  ordinate  and  end  of  chord  equal 
three-quarters  of  the  middle  ordinate. 

Radius  = 


5.0 


sin  ^£  deg.  of  curve 


FROGS  AND  SWITCHES 


89 


Table  2,  which  is  based  on  the  assumption  that  the  degree 
of  curve  is  the  angle  subtending  a  10-ft.  chord,  is  but  a 

.Middle  Ordinate 


\ 


Middle  Ordfnat&  of  20- foot  Chord =5  Inches '200 
Radius  Curve  +£  6aqe  of  Track  = 2°-5?' Curve 

^nearly) 

Radius  of  No.  6  Frog  Turnout  Curve  off 
Tangent 'l53'-IO"-3*>-50'  Curve;  then 
2*-5?'t50-49'=60-4t'nh;ch  cor- 
responds to  an  85' Radius  Curve, 
which  will  be  the  Radius  of  the 
Turnout  if  taken  off  the  Inside 
of  the  Curve 


FIG.  22. — Turnout  off  a  curve. 


modification  decimally  of  the  standard  practice  for  express- 
ing the  degree  of  curvature,  and  is  more  fully  discussed 
under  "  Alignment  on  the  Surface." 


90  MINE  TRACKS 

The  degree  of  the  main  curve  may  be  found  by  stretch- 
ing a  tape  or  string  along  one  of  the  rails  and  then  measur- 
ing the  middle  ordinate.  From  this  middle  ordinate,  the 
degree  of  curve  can  be  taken  by  referring  to  the  table;  the 
degree  of  curve  corresponding  to  the  radius  of  the  lead  curve 
of  the  turnout  can  also  be  taken  from  the  table. 

The  minimum  radius,  which  has  been  adopted  for  curves, 
can  likewise  be  taken  in  terms  of  degree  of  curve  from  the 
table. 

If  the  turnout  is  to  lead  off  the  inside  of  a  curve,  the 
degrees  of  curve  of  both  the  main  track  and  the  proposed 
turnout,  as  computed  for  turning  off  a  tangent,  are  added. 
If  this  does  not  exceed  the  degree  of  curve  of  the  minimum 
radius  allowed,  the  frog  and  turnout  in  question  may  be 
installed.  Should  the  degree  of  curve  exceed  that  corre- 
sponding to  the  allowable  radius,  it  will  be  necessary  to 
repeat  the  process  with  longer  frogs  until  the  combined 
degrees  of  curve  fall  within  the  limit. 

If  the  turnout  leads  off  the  outside  of  the  main  curve, 
the  degree  of  curve  of  both  the  main  track  and  turnout 
track  (as  computed  for  on  a  tangent)  is  found  similarly, 
the  degree  of  turnout  curve  being  subtracted  from  the 
degree  of  curve  of  the  main  track;  the  result  will  be 
the  degree  of  curve  corresponding,  which  can  be  found  in 
terms  of  the  radius  by  referring  to  the  table.  When  this 
has  been  determined,  the  advisability  of  using  a  shorter 
frog  can  be  considered.  In  every  case,  however,  whether 
the  turnout  be  off  the  straight  or  the  inside  or  outside  of  a 
curve,  the  lead  corresponding  to  a  certain  frog  and  switch 
points  should  be  the  same. 


CHAPTER  VII 
LOCATING  THE  TURNOUT 

When  the  site  for  either  the  frog  or  switch  has  been 
decided  upon,  the  rest  of  the  turnout  location  can  be  taken 
from  a  standard  plan.  Within  certain  limits  it  will  often 
be  found  advisable  to  place  the  frog  at  the  nearest  rail 
joint,  taking  care,  however,  that  the  switch  points  do  not 
also  come  at  a  rail  joint. 

If  no  standards  are  available  the  location  of  the  point 
of  either  the  frog  or  switch  should  be  determined.  The 
other  point  can  then  be  moved  along  the  rail,  at  all  times 
keeping  it  in  position  until  the  tangent  distance  from  the 
point  of  frog  to  the  point  of  intersection  of  the  line  of  frog 
and  switch  will  equal  the  distance  from  the  point  of  inter- 
section to  the  heel  of  the  switch. 

Referring  to  Fig.  20,  either  the  frog  or  switch  must  be 
shifted  until  the  distance  T  equals  the  distance  Tl.  This 
plan  is  applicable,  whether  the  frog  is  on  a  curve  or  a  tangent. 

While  an  experienced  trackman  will  usually  be  able 
to  lay  a  fair  turnout  under  varying  conditions,  this  cannot 
always  be  depended  upon.  Particularly  in  the  case  of  a 
new  trackman,  some  governing  and  easily  learned  rules 
should  be  given. 

If  it  is  found  in  laying  a  switch  point  off  a  curve  that 
there  will  not  be  sufficient  clearance  at  the  heel  of  the  switch 
and  the  adjacent  rail,  as  may  occur  in  turning  off  the  inside 
of  a  curve,  it  is  well  to  leave  a  proper  distance  on  the  lead 
or  middle  rail  unspiked  so  that  when  the  switch  is  set  for 
either  track  sufficient  clearance  will  be  obtained. 

91 


92  MINE  TRACKS 

The  switch  points  are  sometimes  bent,  to  accommodate 
this  clearance,  but  this  expedient  for  light  rail  frequently 
results  in  having  the  points  break  after  a  little  wear  at  the 
place  where  the  rail  bender  has  been  applied. 
LADDER  TRACKS 

A  ladder  track  is  one  from  which  a  number  of  parallel 
tracks  branch,  the  frogs  being  located  at  intervals,  depend- 
ent upon  the  centers  required  between  tracks  and  the  frog 
number  used.  In  Fig.  23,  A  is  the  ladder  track,  and  B, 
C  and  D  are  the  branches. 


Angle  of Trog-:     \  \  MfllN  rff/7C« 


FIG.  23.— Ladder  tracks. 

The  distance  required  between  frog  points  is  found  by 
dividing  the  distance  desired  between  track  centers  by 
the  sine  of  the  frog  angle.  The  ladder  track  should  be  on 
an  angle  to  the  main  tracks,  equal  to  the  frog  angle  to  be 
used. 

The  ladder  track  makes  a  better  and  more  symmetrical 
layout  where  several  turnout  tracks  are  to  be  laid,  than 
having  each  turnout  track  branch  off  the  one  adjacent, 
the  usual  method,  used  around  mines. 


CHAPTER  VIII 
BOOK  OF  RULES 

It  is  obvious  that  in  order  to  secure  any  high  degree 
of  perfection  in  the  standardization  and  installation  of 
track  it  will  be  imperative  to  have  definite  instruc- 
tions and  plans  to  govern  and  guide  the  workman  in  its 
construction. 

The  instructions  should  be  concise  and  easily  understood ; 
the  routine  work  should  be  covered  fully;  and  the  duties  of 
the  trackman,  and  those  indirectly  concerned,  clearly 
specified.  This  will  preclude  any  evasion  of  responsibility; 
and,  on  the  other  hand,  by  prescribing  the  course  to  be 
pursued  under  different  conditions,  remove  to  a  great 
extent  the  burden  of  decision  from  the  workman.  This 
policy  will  help  to  develop  more  quickly  young  and  in- 
experienced trackmen  and  tend  to  conserve  material  and 
time  with  the  more  efficient.  Able  trackmen  are  not  pro- 
duced over  night,  and  there  is  a  vast  waste  of  time  and 
many  inferior  layouts  made  before  any  great  proficiency  is 
acquired. 

Those  concerned  in  any  way  with  the  track  installation 
and  the  preliminary  work  on  which  it  is  to  a  great  extent 
dependent,  should  be  furnished  with  copies  of  the  rules, 
plans  and  all  information  in  reference  to  them,  and  care 
taken  to  insure  that  they  are  thoroughly  familiar  with  these 
instructions.  It  will  be  conceded  that  more  efficie'nt  and 
uniform  results  will  be  obtained  if  such  a  course  is  pursued 

93 


94  MINE  TRACKS 

than  if  the  workmen  are  all  left  to  depend  upon  their  own 
judgment. 

The  engineering  department  should  lay  out  the  work 
in  a  manner  that  will  utilize  the  standard  equipment 
supplied  to  the  trackman.  The  curves  should  be  of  a  radius 
to  correspond  to  the  regulation  frog  to  be  used,  so  that  the 
turnout  can  be  installed  with  the  frog  fitting  the  curve 
and  requiring  no  compromising  in  its  installation.  To  do 
this,  a  radius  that  will  be  tangent  to  the  end  of  the  frog 
that  joins  the  curve,  and  at  the  same  time  conform  to  the 
portion  between  the  switch  and  the  frog,  should  be 
used. 

.  The  mine  foreman,  or  his  assistants,  should  see  that 
their  work  is  symmetrical  and  conforms  to  the  plans.  A 
failure  on  the  part  of  either  will  compel  a  distortion  of  the 
trackwork. 

The  following  book  of  rules  is  here  given  as  a  skeleton 
or  model  around  which  the  many  rules  demanded  by  local 
conditions  can  be  built.  This  plan  is  an  adaptation  of  the 
practice  of  many  standard-gage  roads  that  regulate  their 
maintenance-of-way  employees  with  instructions  governing 
their  various  duties.  Some  of  the  rules  have  been  carried  to  a 
refinement  which  it  is  realized  will  be  impossible  to  obtain  in 
actual  practice;  however,  they  furnish  a  standard  which  ex- 
perience will  determine  how  close  it  is  required  to  approach. 

The  underlying  reason  for  the  rules  should  be  explained 
to  those  concerned,  and  meetings  held  at  intervals  where 
any  suggestions  or  revisions  can  be  discussed.  This  policy 
will  instill  enthusiasm  and  a  spirit  of  rivalry  among  the 
trackmen,  which  if  fostered  should  be  productive  of  the 
most  beneficial  results. 

It  may  be  pertinent  to  state  here  that,  to  produce  the 
most  efficient  transportation,  careful  attention  must  be 


BOOK  OF  RULES  95 

likewise  given  to  improving  the  running  parts  of  the  rolling 
stock,  so  that  the  results  to  be  expected  from  well-installed 
track  may  not  be  nullified  by  poor  cars. 

There  are  many  ways  of  performing  almost  any  task. 
Scientific  management  (so-called)  has  shown  the  advantages 
to  be  derived  in  selecting  and  perfecting  one  method  and 
performing  in  their  logical  sequence  the  various  operations 
involved. 

The  considerations  or  formulae  which  determine  the 
following  rules  will  be  found  in  the  preceding  articles. 

In  conclusion  I  would  say  that  even  though  the  best 
practice  may  not  be  achieved  in  the  first  set  of  rules,  an 
inferior  practice  well  carried  out  will  accomplish  more 
than  a  good  system  indifferently  followed. 

(A)  GENERAL  RULES 

1.  The  foreman  of  each  colliery  must  supply  copies  of  these 
rules  and  standards  to  the  trackmen  and  repairmen;  and  the 
assistant  foreman  must  enforce  obedience  to  them  and  report 
to  the  district  superintendent  all  violations  and  the  action  taken 
thereon.    Every  employee  with  duties  in  any  way  prescribed 
by  these  rules  must  be  conversant  with  them. 

2.  The  fact  that  any  person  enters  or  remains  in  the  service 
of  the  company  will  be  considered  assurance  of  willingness  to 
obey  its  rules. 

3.  In  the  event  of  any  doubt  as  to  the  meaning  of  any  plan, 
or  if  additional  data  is  required,  application  should  be  made  to 
the .* 

4.  Meetings  will  be  held  at  least  once  every  3  months  by 
the ,  where  a  review  will  be  taken  of  the  various 

1  Where  blanks  occur  in  these  rules  they  should  be  filled  with  the 
title  of  the  proper  official,  or  necessary  data,  in  this  case  probably 
the  division  engineer. 


96  MINE  TRACKS 

rules,  and  suggestions  for  alterations,  improvements  or  additions 
to  the  existing  standards  received. 

5.  Safety  is  of  prime  importance  in  the  performance  of  any 
duty;  every  precaution  must  be  taken  .to  avoid  accident  to  the 
workmen  themselves  or  others. 

6.  Workmen  are  responsible  for  the  care  and  condition  of  their 
tools. 

7.  All  work  must  be  left  in  a  safe  condition. 

8.  Any  work  that  interferes  with  the  safe  passage  of  trips  at 
their  normal  speed  is  an  obstruction,  and  except  in  emergencies 
should  be  attempted  only  after  working  hours. 

9.  Material  must  not  be  piled  along  the  sides  of  haulageways. 

10.  Only  such  an  amount  of  material  must  be  stored  inside  as  is 
required  for  immediate  use,  and  care  must  be  taken  to  place  this 
so  as  to  permit  free  passage  on  the  ditch  side  of  the  gangway. 

11.  Tools  and  special  material  must  be  kept  under  lock  and 
key  and  not  given  out  or  loaned  without  proper  authority. 

(B)  ROADBED 

1.  The  roadbed  on  all  new  work,  or  wherever  roadbed  is  re- 
newed, should  conform  to  the  standard  plan. 

2.  The  drainage  ditch  should  be  driven  full  width  and  depth  at 
the  same  time  as  the  heading  or  tunnel,  and  maintained  clear 
within  25  ft.  of  the  face  by  the  party  driving  same. 

3.  The will  determine  what  material  shall  be  used 

for  roadbed,  and  see  that  same  is  adhered  to.     Ballast  is  graded 
as  follows:  (1)  Broken  stone,  excellent.     (2)  Ashes,  good.     (3) 
Breaker  slate,  fair.     (4)  Coal  and  refuse,  poor. 

4.  Where  rock  is  used  for  ballast,  it  must  be  broken  to  a  size 
that  will  pass  through  a  3-in.  ring. 

5.  All  main  haulage  roads  should  have  at  least  2  in.  of  ballast 
beneath  the  tie,  wherever  possible. 

(C)  TIES 

1.  Ties  must  be  laid  16  to  a  30-ft.  rail  and  18  to  a  33-ft.  rail. 
They  must  be  placed  at  right  angles  to  the  rail  and  properly  and 
evenly  spaced. 


BOOK  OF  RULES  97 

2.  Whether  or  not  ties  are  of  uniform  lengths,  the  ends  of  the 
ties  on  the  ditch  side  of  the  track  should  be  aligned  at  an  even 
distance  from  the  rail. 

3.  Selected  ties  should  be  used  on  all  main  haulageways. 

4.  The  standard  square  ties  in  graded  lengths,  conforming 
with  both  the  turnout  and  main  tracks,  should  be  used  at  all 
turnouts  and  switches. 

5.  Joint  ties  should  be  selected  and  be  as  near  the  same  size  as 
possible. 

6.  When  a  spike  is  drawn  from  a  tie,  the  hole  should  be  plugged 
before  a  spike  is  again  driven  in  this  tie. 

7.  As  ties  become  unfit  for  service,  they  should  be  removed  in 
the  manner  known  as  " spotting"  and  not  in  continuous  sections. 

8.  Ties  removed  that  cannot  be  used  for  any  other  purpose 
should  be  loaded  and  taken  out  of  the  mine  at  once. 

9.  All  ties  must  be  well  tamped  and  particular  attention  given 
to  tamping  under  the  rail. 

10.  On  account  of  drainage  and  tamping  considerations,  the 
practice  known  as  corduroying — that  is,  inserting  new  ties  between 
those  partially  rotted  without  removing  the  rotten  ties — must 
not  be  employed  except  in  cases  where  mule  haulage  only  is  in 
service. 

11.  Steel  ties  alone  should  only  be  used  in  locations  where  the 
roof  is  low  and  no  acid  water  abounds. 

12.  Where  fishplates  are  used,  a  selected  tie  should  be  placed 
directly  under  the  rail  joint. 

13.  Where  angle  bars  are  employed,  the  rail  joint  should  be 
suspended  with  a  selected  tie  under  the  angle  bar  on  each  side  of 
the  joint  so  as  to  give  the  angle  bar  a  good  and  sufficient  bearing. 

14.  Ties  not  up  to  specifications  should  not  be  laid  until  the 
foreman's  attention  has  been  called  to  them  and  his  instructions 
received. 

15.  Tie  Specifications: 

(a)  Mine  ties, — ft.  long,  must  be  first-class  sound  timber  and 
stock  well  manufactured,  not  less  than  —  nor  over  —  in.  thick, 
with  not  less  than  —  in.  faces  at  small  end.  Such  ties  may  be  of 


98  MINE  TRACKS 

either  oak,  chestnut,  hemlock,  ash,  soft  maple,  ironwood,  locust, 
hickory  or  pitch  pine.  They  must  be  hewed  or  sawed  on  two 
parallel  faces. 

(6)  Outside  ties,  —  ft.  long,  must  be  first-class  sound  timber  and 
stock  well  manufactured,  —  to  —  in.  thick,  with  not  less  than  — 
in.  faces  at  small  end,  and  be  of  either  oak,  chestnut,  locust  or 
pitch  pine,  and  hewed  or  sawed  on  two  parallel  faces. 

(c)  Notched  ties,  —  ft.  long,  must  be  not  less  than  —  in.  in 
diameter  under  bark  at  small  end,  and  of  the  same  kinds  of  timber 
as  (a)  mine  ties. 

16.  (a)  Mine  ties  (a)  should  be  used  for  general  work  inside. 
(6)  Ties — ft.  long  should  be  used  for  outside  work,  (c)  Notched  ties 
may  be  used  only  for  chamber  work  where  wood  rail  is  in  service. 

(D)  RAIL  AND  SPIKES 

1.  Rails  must  be  laid  with  broken  joints;  that  is,  the  joints  of 
one  line  should  be  as  nearly  opposite  as  is  practicable  the  centers 
of  the  rails  on  the  opposite  line. 

2.  Short  rails  are  only  advisable  for  temporary  work.     No 
rail  under  10  ft.  in  length  is  permitted  on  main-haulage  roads. 

3.  Rails  must  be  spiked  in  full  and  each  spike  driven  home 
perpendicularly  with  full  hold  on  the  rail.     The  last  blow  should 
be  a  light  one,  to  avoid  breaking  the  spike  under  the  head. 

4.  The  shall  see  that  not  more  than  enough 

spikes  to  last  —  days  are  given  out  at  one  time  to  any  workman. 

5.  Spikes  should  be  staggered;  that  is,  the  outside  spikes  of 
both  rails  must  be  toward  the  same  side  of  the  tie  and  the  inside 
spikes  toward  the  opposite  side. 

6.  Rails  should  be  laid  true  to  gage.     No  deviation  from  this 
rale  may  be  made  except  on  curves  as  shown. 

7.  The  gage  on  all  curves  whose  radius  is  less  than  —  ft.  should 
be  widened  1  in. 

The  gage  on  all  curves  whose  radius  is  200  ft.  should  be 
increased  —  in.;  for  250-ft.  radius,  —  in.;  for  300-ft.  radius, 
—  in.,  etc. 


BOOK  OF  RULES  99 

8.  On  straight  track  both  rails  must  be  on  the  same  level, 
except  on  approaches  to  curves,  where  the  proper  elevation  must 
be  given  the  outer  rail. 

9.  The  superelevation  for  the  outer  rail  for  maximum  speed 
allowed  must  be: 

Gage . 

Underground,    On  the  surface, 
in.  in. 

For  a    30-ft.  radius  curve 

For  a    40-ft.  radius  curve 

For  a    50-ft.  radius  curve 

For  a    60-ft.  radius  curve .  

For  a    80-ft.  radius  curve 

For  a  100-f t.  radius  curve 

For  a  150-ft.  radius  curve ........ 

For  a  200-f t.  radius  curve ........ 

10.  The  track  level  should  be  tested  frequently  and  always 
used  when  surfacing  track. 

11.  (a)  —  Ib.  rail  shall  be  the  lightest  rail  laid  and  be  used 
only  for  buggy  work.     (6)  —  Ib.  rail  shall  be  the  lightest  rail  used 
where  the  regular  mine  cars  run.     (c)  —  Ib.  rail  shall  be  the  lightest 
rail  used  where  locomotive  haulage  is  employed,     (d)  —  to  — 
Ib.  rail  may  be  used  on  main-haulage  roads,  and  for  heavy  outside 
traffic  by  special  arrangement. 

12.  "Dead"  steel  rail — that  is,  old  rail  unfit  for  regular  haulage 
— shall  be  used  wherever  possible  for  chamber  work. 

13.  Wood  rail  shall  be  used  only  for  heavy  pitching  chambers 
and  slants  where  the  "dead"   rail  cannot  be  utilized. 

14.  Wood  rail  not  conforming  to  specifications  should  not  be 
used  until  the  foreman's  attention  has  been  called  to  its  defects 
and  his  permission  to  lay  it  obtained. 

15.  Specifications  for  wood  rail:  Wood  rail  should  be  first- 
class  sound  timber  and  stock  well  manufactured  and  sawed  — 
by  —  in.  and  in  —  to  —  ft.  lengths;  it  must  be  square  edged  and 
sound,  of  beech,  birch,  maple,  oak  or  ash. 

16.  Steel  rail  must  not  be  dropped  from  the  sides  of  railroad 
cars. 


100  MINE  TRACKS 

17.  The  size  of  spikes  should  be  for  —  ties  —  inches. 

18.  The  size  of  spikes  should  be  for  —  ties  —  inches. 

19.  The  track  gage  must  be  placed  square  with  the  track, 
and  the  rail  held  tight  against  it,  until  the  spikes  are  driven. 

20.  The  locomotive  engineer  or  driver  shall  report  the  location 
of  any  poor  roadbed,  and  all  derailments  and  the  .cause  thereof 
to  the . 

21.  Spikes  in  abandoned  ties  or  track  must  be  reclaimed  by 


(E)  CURVES 

1.  Lines  will  be  given  by  the  engineers  for  all  tunnels  and  rock 
curves,  and  no  tunnel  or  curve  shall  be  started  without  such  a  line. 

2.  It  is  the  duty  of  the  mine  foreman  to  see  that  all  lines  are 
rigidly  adhered  to. 

3.  A  —  ft.  radius  curve  is  the  minimum  curve  allowed. 

4.  When  curves  are  necessary  in  following  the  irregularities 
of  a  bed,  the  curve  offset  for  a  —  chord  should  not  be  greater 
than  —  ft. 

(F)  ANGLE  BARS,  TIE-PLATES  AND  RAIL  BRACES 

1.  All  rail  25  Ib.  or  over  should  be  laid  with  joint  fastenings. 

2.  All  rail  joints  where  mechanical  haulage  is  in  service  should 
be  laid  with  angle  bars. 

3.  All  joint  fastenings  must  be  applied  with  the  full  number  of 
bolts,  washers  and  nuts,  screwed  up  and  kept  tight. 

4.  The  ties  at  joint  fastenings  should  be  laid  as  indicated  in 
Rules  C  13  and  C  14. 

5.  Where  heavy  locomotives  are  in  service  and  the  flange  of 
the  rail  cuts  the  tie,  requiring  frequent  notching,  tie-plates  may 
be  used  by  permission  of  the . 

6.  Tie-plates  may  be  used  where  the  traffic  wears  out  the  flange 
of  the  rail  before  the  head  has  given  full  service,  and  where  the 
rail  cuts  the  spikes  by  applying  to  the  —       . 

7.  Rail  braces  may  be  used  on  curves  where  it  is  hard  to  main- 
tain the  gage  by  applying  to  the . 


BOOK  OF  .&J.LES  101 

8.  Rail  braces,  when  used,  should  be  applied  to  both  rails. 

9.  Rail  braces  must  not  be  applied  where  tie-plates  are  used. 

(G)  FROGS  AND  SWITCHES 

1.  A  No. cast  frog  shall  be  used  on  all  new 

chamber  switches  of  —  Ib.  rail. 

2.  A  No.  —  builtup  frog  shall  be  used  on  all  new  chamber 
switches  of  —  Ib.  rail  or  over. 

3.  A  No. frog  shall  be  used  for  general  use. 

4.  A  No. frog  may  be  used  in  cases  where  the 

traffic  is  fast  and  heavy. 

5.  A  No. frog  may  be  used  outside  by  special 

arrangement  where  the  locomotives  are  large  and  the  traffic  is 
unusually  fast  and  heavy. 

6.  A  —  ft.  tongue  switch  should  be  used  with  the  cast  frog. 

7.  A  —  ft.  split  switch  should  be  used  with  the  No.  —  and 
No.  —  builtup  frogs. 

8.  A  —  ft.  split  switch  should  be  used  with  the  No.  —  and 
No.  —  frogs. 

9.  Frogs  inside  the  mine  must  be  placed  to  conform  to  the  ribs 
of  the  curve  and  not  the  nearest  rail  joint. 

.  10.  The  lead  of  a  frog  to  be  located  on  a  curve  should  be  the 
same  as  the  number  of  frog  adopted  calls  for — that  is,  no  difference 
should  be  made  in  the  lead  whether  the  turnout  is  off  a  tangent  or 
a  curve. 

11.  When  the  frog  is  located  on  a  curve,  the  sum  of  the  degree 
of  curve  of  the  main  track  and  the  degree  of  curve  corresponding 
to  the  frog  should  not  exceed  —  deg.    The  degree  of  curve  of  the 
main  track  may  be  found  by  measuring  the  ordinate  of  a  10-ft. 

chord  and  referring  to  Table  — ,  page .    The  degree  of  curve 

corresponding  to  the  turnout  radius  may  also  be  taken  from  the 
same  table. 

12.  The  rail  connecting  the  frog  and  the  heel  of  the  switch 
should  conform  to  the  length  shown  on  the  standard  layout  draw- 
ings.   One  rail  should  be  bent  to  the  required  radius  and  should 
be  drilled,  and  a  supply  kept  constantly  in  stock. 


102  MINE  TRACKS 

13.  The  distance  from  the  switch  to  the  frog  must  agree  with 
the  standards,  so  as  to  make  the  connecting  rails  interchangeable. 

14.  Where  possible,  the  switch  lever  should  be  placed  on  the 
ditch  side  of  the  gangway,  or  heading. 

15.  Switch  stands  must  be  used  at  all  switches  where  mechanical 
haulage  is  employed. 

16.  The  switch  with  spring  should  be  used  at  all  main  switches; 
for  general  use,  the  type  without  the  spring  must  be  employed. 

17.  The  switch  and  spring  must  be  kept  clean  and  well  oiled. 

18.  When  a  turnout  is  to  be  laid,  a  complete  set  of  parts  should 
be  delivered  to  the  proper  location  in  ample  time. 

19.  Bills  of  material  for  each  turnout  design  used  are  as  follows : 
These  bills  of  material  to  be  prepared  for  standard  turnout 

installations.     The  standards  adopted,    of    course,  will  be  pe- 
culiar to  each  mine  or  company. 


INDEX 


Acid  water,  5,  23,  24 
Angle  bars,  23,  26,  27 

Ballast,  29-30 

corrosion  of  rail,  29 
drainage,  29-30 

Cinders,  29 

Corduroying,  24 

Crystallization,  9 

Curves,  alignment  of,  31-39 

compensation  for,  36-37,  54- 

60 

formulae,  40-44 
increase  of  gauge,  63-66 
radii,  34-36,  41-44 
resistance,  36-37,  65 
superelevation  of,  61-63 
surface,  38-44 
symbols,  38-44,  40-41 
underground,  31,  38 

Drainage  ditches,  46-47 
Draw  bar  pull,  36-37,  48-54 

Elevation  of  outer  rail,  61-63 
Expansion  of  rail,  10 

Fish  plates,  23,  26,  27 
Friction,  coefficient  of,  11 

curvature,  36-37,  48-51,  54- 
60,  63-66 

journal,  52-55 


Frogs,  68-74,  76-79 
cast,  70,  71 
determination    of    number, 

69-70 

guard  rails,  71-72 
movable  points,  73,  74 
rail,  70,  72 
shrouds,  70-72 

-  standardization  68,  69,  76-79 
tables,  76-79 
track  crossing,  74 

Gauge  on  curves,  63-66 
Grades,  boards,  56-58 

car  journal  resistance,  52-55 

compensation,  55-60 

construction,  55,  57,  58 

designation  of,  45 

determination  on  surface,  45 

drainage,  46,  47,  51 

gravity,  59-63 

mining  disadvantages,  51,  54 

tables,  56-58 

theoritic,  48-50,  58 

track  resistance,  48-51 

underground,  45-46,  48-50, 

52-55 
Guard  rails,  66-67,  71-72 

shrouds,  70-72 


Ladder  tracks,  92 
Latches,  74-75 


103 


104 


INDEX 


Projection  of  haulage  roads,  31-34 
curve      alignment,      31-34, 

38-39 

formulae,  40-44 
radii,  34-36 

short,  43-44 
resistance,  36-37 
economic  considerations,  34- 

37 

geologic  considerations,  31 
preliminary  location,   38-40 
surface,  38-44 
underground,  31-38 


Rail,  1-11 

acid  water,  5,  23-24 

annealing,  9 

benders,  8 

bending  moment,  14-15 

braces,  27-28 

coefficient  of  friction,  11 

corrosion,  5,  23,  24,  29 

creep,  10 

crystallization,  9 

deflection,  19-20 

dimensions,  5,  6 

dishes,  6,  22 

durability,  3,  4 

expansion,  10 

impact  stresses,  13 

joints,  6,  7,  23 

spikes,  25 

stiffness,  2,  13,  19 

strength,  3,  14,  15 

wear  resistancy,  4,  27,  28 

weight  required,  1,  16,  17,  25 

wood,  10,  11,  24 
Rail  bender,  8 


Rail  braces,  27-29 

flange  preservation,  28 
Roadbed,  29-30 

Rules  for  trackmen,  92-100 
advantages,  93 
angle  bars,  100 
coordination  of  work,  93,  94 
curves,  99,  100 
frogs,  100 
general  rules,  95 
rail,  98 

rail  braces,  100 
roadbed,  96 
spikes,  98 
standardization,  93 
superelevation,  98,  99 
switches,  100 
tie  plates,  100 
ties,  100 

Shrouds  for  frogs,  70-72 
Spikes,  25-26 

Superelevation  of  rail,  61-63 
Switches,  66,  74,  82 

angle  of,  76,  82,  87 

spring,  75 

stub,  75 

ties,  24 

underground,  75 

Tie  plates,  27-29 

rail  flange  preservation,   28 
Ties,  12-24 

ballast,  12,  13,  18 

corduroying,  24 

dimensions,  12,  21,  22,  25 

failures,  21,  27,  28 


INDEX  105 

Ties,  notched,  24  Turnouts,  ladder  tracks,  92 
plates,  27,  28  location  of,  91 

spacing,  12-14,  16-18,  21,  23  off  curves,  87-89 

spikes,  25  radii,  88-90 

steel,  24  standardization,  80,  82,  86, 

switches,  24  87 

wood  preferred,  12,  24  tables,  83-85 

Turnouts,  80-92 

formulae,  80-82,  87  Wood  rails,  10,  11,  24 


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